How to Find a Product to Sell Online Without Guessing

Most “what to sell online” advice is a list of trending products. The problem is that everyone else reads the same list. By the time a product shows up as “trending,” the marketplaces are full of sellers competing on price.

A better approach is to treat product selection as research. You’re looking for a product with 3 things: steady demand, a gap you can fill better than existing sellers, and margins that survive fees, shipping and marketing. This guide shows you how to check each one with tools that are mostly free.

What makes a good product to sell online

Before you research anything, know what you’re scoring. A good first product usually has most of these:

Trait	Why it matters	Red flag
Steady or growing demand	Sales don’t vanish after a fad	Spiky, one-season interest
Clear customer problem	Easier to market and describe	“Nice to have” with no reason to buy
Room to stand out	You can compete on more than price	Identical listings from dozens of sellers
Healthy margin	Pays for ads, returns and growth	Profit only at the very top of the price range
Small and light	Cheaper shipping and storage	Heavy, bulky or fragile
Low regulatory risk	Fewer certifications and liability issues	Children’s products, supplements, cosmetics without a plan
Repeat purchase potential	Higher lifetime value per customer	One-and-done purchases only

You don’t need all 7. But a product that fails on demand or margin will struggle no matter how good your store is.

Research ideas, demand and gaps

Step 1: Start with what you know

The best product ideas often come from your own life: a hobby, a job, a community or a frustration. You already know the vocabulary, the problems and where those customers hang out online. That makes product research, writing and marketing much easier.

Write down 10 ideas from:

• Hobbies and communities you belong to
• Problems you’ve solved for yourself or others
• Products you’ve bought and been disappointed by
• Niches where you have professional expertise
• Local or cultural products you can source well

Don’t judge the ideas yet. The next steps filter them.

Step 2: Check search demand

Demand research tells you whether people are actively looking for a product, and whether that interest is growing, stable or fading.

Google Trends shows how interest in a search term changes over time and by region. Google explains that Trends data is normalized and scaled from 0 to 100 based on a topic’s share of all searches, so it shows relative popularity, not absolute search volume. Use it to:

• Compare 3 to 5 related terms to see which wording people use
• Set the time range to 5 years to spot fads versus steady demand
• Check for seasonality, such as spikes every December

Google Keyword Planner, a free tool inside Google Ads, gives estimated average monthly searches and related keyword ideas. Google notes that its search volume figures are rounded. Use it to find the specific phrases buyers type, such as “waterproof dog coat for large dogs” rather than “dog coat.”

Marketplace search suggestions on Amazon, Etsy and eBay show what shoppers type as they search. Type your product idea and note the autocomplete suggestions; they reflect real buyer language.

What you want to see: steady or growing interest over several years, plenty of specific long-tail searches and seasonal patterns you can plan around.

Step 3: Mine marketplace reviews for gaps

Reviews are the most underrated research tool. Customers tell you exactly what’s wrong with existing products.

1. Find the top 5 to 10 listings for your product on Amazon, Etsy or another marketplace.
2. Read the 1, 2 and 3 star reviews. These are where buyers explain what disappointed them.
3. Note recurring complaints: wrong size, poor materials, confusing instructions, breaks quickly, missing feature, poor packaging.
4. Read the 5 star reviews for what buyers love, so you keep it.
5. Check questions in the Q&A sections for features buyers wish existed.

If the same complaint appears across many listings, you’ve found a gap. A product that fixes it, and says so clearly, has a reason to exist.

Also look at competition. Marketplace best-seller lists, such as Amazon’s Best Sellers, show what’s selling now. Many near-identical listings competing on price usually signal a crowded market; a few strong sellers with fixable complaints signal opportunity.

Key takeaway: Demand proves people want the product. Bad reviews prove existing options aren’t good enough. You want both before you invest in inventory.

Check margins, sourcing and rules

Step 4: Do the margin math

A product people want can still lose money. Run the numbers before ordering stock. Calculate profit per order:

Profit per order = selling price - product cost - shipping to customer - packaging - payment and platform fees - returns allowance - marketing cost per sale

Here’s an illustrative example for a $40 product:

Line item	Example amount
Selling price	$40.00
Product cost, including freight and duties to you	-$10.00
Shipping to customer (if you offer free shipping)	-$7.00
Packaging	-$1.00
Payment processing (about 3% plus a fixed fee)	-$1.50
Returns and damages allowance (5% of price)	-$2.00
Marketing cost per sale	-$12.00
Profit per order	$6.50

Your numbers will differ, but the lesson holds: a product that looks like a 4x markup can end up with thin profit once shipping and ads are included. As a rule of thumb, look for products where the selling price is comfortably several times your landed cost, so there’s room for marketing.

Ways to improve the math:

• Bundle items to raise average order value
• Choose smaller, lighter products to cut shipping
• Find products customers reorder, so you don’t pay to acquire them every time
• Raise prices by fixing the problems competitors’ reviews reveal

For a full budget beyond one product, see how much it costs to start an online store.

Step 5: Check sourcing and regulations

Before you commit, confirm you can source the product reliably and legally.

Sourcing options include making it yourself, buying wholesale, private label manufacturing, print on demand and dropshipping. Each has different costs and risk. If you’re considering dropshipping, read how dropshipping works first, especially the sections on shipping times and supplier risk.

Order samples from 2 or 3 suppliers. Check quality, packaging and how long delivery takes.

Check regulations. Some categories carry legal requirements:

• Children’s products: the CPSC says products designed or intended primarily for children 12 and under generally need third-party testing by a CPSC-accepted lab and a Children’s Product Certificate issued by the manufacturer or importer.
• Cosmetics, supplements and food: FDA rules apply, and some states add their own.
• Electronics and batteries: may require certifications and carry shipping restrictions.
• Trademarked or licensed designs: selling them without permission can get listings removed and lead to legal claims.

This is general information, not legal advice. If your product is regulated, talk to a compliance professional before you sell.

Step 6: Test small before you scale

Don’t order 1,000 units on research alone. Validate with real buyers:

1. Pre-sell or take preorders with a clear ship date.
2. List on a marketplace to test demand with built-in traffic; compare options in Shopify vs Etsy for new sellers.
3. Run a small ad test to a product page and measure clicks, add-to-carts and purchases.
4. Order a small first batch, even if the per-unit cost is higher.
5. Collect feedback from early buyers and adjust the product or listing.

If the test sells at your target price and cost per sale, scale up. If not, change one variable, such as price, photos, offer or audience, and test again, or move to the next idea.

Research tools at a glance

Tool type	Examples	What it tells you	Cost
Search trend tools	Google Trends	Relative interest over time and seasonality	Free
Keyword tools	Google Keyword Planner	Estimated search volume and related phrases	Free with a Google Ads account
Marketplace search	Amazon, Etsy, eBay autocomplete and best-seller lists	Buyer language and what’s selling	Free
Reviews	Marketplace reviews and Q&A	Customer pain points and gaps	Free
Product research software	Marketplace analytics tools	Estimated sales and competition	Paid subscriptions
Social listening	Forums, social media groups	Unfiltered problems and wishes	Free

AI chatbots can help brainstorm niches and summarize review themes quickly; see how to use AI chatbots for everyday tasks. Always verify demand with real data, because chatbots can’t see current sales.

Where to start this week

1. List 10 product ideas from your own hobbies, work and frustrations.
2. Check each in Google Trends over 5 years and cut the fads.
3. For the top 3, read low-star reviews on 5 competing listings.
4. Run the margin math with real supplier quotes.
5. Order samples for your best 1 or 2 ideas.

Then follow our step-by-step guide on how to start an online store to launch.

The bottom line

Finding a product to sell online isn’t about catching the next trend. It’s about proving demand, finding a gap in what’s already sold, and confirming the margins work after every cost. Use free tools for research, test with a small batch, and let real sales data decide what you scale.

Sources

• Google Trends Help: FAQ about Google Trends data — normalization and the 0 to 100 scale
• Google Ads Help: Use Keyword Planner — free keyword research inside Google Ads
• Google Ads Help: About Keyword Planner forecasts — rounded search volume statistics
• CPSC: Children’s Product Certificate — third-party testing and certification for children’s products