Three days ago, a sourcing contact bought a hair dryer in bulk at Walmart and shipped 200 units straight to FBA. Buy price: $19.50. Marcus had been watching the same SKU for six weeks. He saw the Walmart listing at $26 and passed — nothing about the number looked interesting. What he didn't know was that $26 had been the floor since January, and $19.50 was a four-year low. A genuine window. It stayed open for about 36 hours.

He uses Keepa. He uses it every day and trusts it. For retail arbitrage sourcing, Keepa shows you exactly what it is designed to show: the Amazon sell-side history. The buy box trend over the past two years, the BSR movement, the seasonal price pattern on the listing. All of it accurate. None of it telling him whether the Walmart number he was looking at was genuinely cheap. If you're asking whether you need a Keepa alternative, the honest answer is probably not — but you may need something Keepa was never designed to be.

That distinction is worth holding onto, because the two are not interchangeable. Keepa solves a specific problem extremely well. Retail arbitrage requires you to solve two problems simultaneously, and the second one lives in a different retailer's database entirely.

What Keepa Gets Right

Keepa's value for Amazon sellers is real and specific. It stores Amazon price history at the ASIN level — buy box movements, third-party seller price fluctuations, historical best seller rank — and renders it in charts that let you see at a glance whether a listing has been stable, climbing, or in freefall over the past several years. For understanding the sell side of a trade, it is still the best free reference you can pull up before committing inventory. That is not a minor capability.

The BSR history is particularly useful for building conviction on a SKU before you move on it. A product with a stable rank and a gradually rising buy box price is a very different bet than one with a volatile rank and a price that has been declining for eight months. Keepa surfaces that story in a few seconds, for free, on any Amazon ASIN. For the question "will this listing support my sell price over the next sixty days," Keepa gives you the historical evidence to reason from.

The broader point is that Keepa's limitations have nothing to do with quality or effort. It was built to give Amazon marketplace operators a thorough, reliable view of Amazon price history, and it delivers that. Experienced resellers pull Keepa before they make a buy decision — not because it tells them whether to buy, but because it tells them whether the Amazon price environment can support the trade. That question has to be answered. Keepa answers it well. What it cannot answer is the corresponding question about the product's cost at the retailer where they actually source.

The Question Keepa Cannot Answer

Retail arbitrage is a two-sided trade. You buy at one price from one retailer, and sell at another price on Amazon. The spread between those two prices — after FBA fees, prep costs, and inbound shipping — is your margin. Understanding the sell side is Keepa's job, and it handles it well. The buy side is a different problem entirely, and it lives outside any Amazon-native tool by design.

When you look at a product on Walmart and see a price of $31, Keepa gives you no context for whether that number is notable. It might be the lowest that product has been priced in eighteen months, or it might be the price it has sat at since spring. The difference between those two scenarios is the difference between a genuine opportunity and a normal day at retail. Keepa was built for Amazon — Walmart and Target price histories do not exist anywhere in its architecture, not as an oversight, but because that was never the problem it was built to solve.

This is a structural observation, not a criticism. Amazon marketplace intelligence and retail arbitrage sourcing are related activities, but they are not the same activity. They require different information at different points in the decision. A reseller who uses only Amazon-side data to evaluate buy-side decisions is working with half the equation — and the missing half is the one that determines whether a trade is worth making. Most resellers who pass on genuine opportunities are not missing them because they are inattentive. They miss them because the information they need never arrives.

What Retail Arbitrage Actually Requires

To evaluate a retail arbitrage opportunity correctly, two things need to be true at the same time. First, the Amazon sell price must be stable or elevated — ideally trending up, not declining. Second, the buy price at Walmart or Target must be genuinely compressed relative to its own recent history, not just relative to the Amazon listing price. Answering the first question without the second is how resellers end up paying standard Walmart pricing, calling it arbitrage, and then wondering where the margin went.

The mechanics are not complicated, but the information gap makes them easy to get wrong. A product selling on Amazon for $54 might be listed at $32 at Walmart today. Whether $32 is worth acting on depends entirely on what Walmart normally charges for that product. If the standard Walmart price has been $44 since February, $32 is a genuine compression and potentially worth moving on quickly. If Walmart has been running it at $29 all spring and the current number is a slight uptick, there is no spread — it just looks like one because the historical baseline is missing.

That baseline problem becomes especially acute around seasonal buying windows. Pre-Prime Day compression, post-holiday clearance cycles, end-of-quarter inventory flushes — all of them require knowing whether today's buy-side price is actually cheap relative to what it normally is. Without cross-retailer price history, you are comparing a current number against an impression, not a record. The resellers who execute these windows consistently are not more disciplined about checking prices — they have a more complete picture of both sides of the trade before they move. The timing mechanics for Prime Day specifically follow the same logic, but the structural point applies every month of the year.

How to Close the Gap

PriceTrail tracks prices on Amazon, Walmart, and Target from the same dashboard and stores price history for every listing you follow. The mechanic is straightforward: paste the product URL from whichever retailer you are sourcing from, set a target price — the floor where your margin holds — and wait for the alert. The tool watches the SKU and notifies you when that threshold is hit. No manual tab rotation, no spreadsheet to maintain, no finding out after the fact.

For the Walmart hair dryer Marcus missed, the workflow would have been simple. Add the Walmart listing, set a target at $21 or below, and go on with the day. When the price dropped to $19.50 at some point in that 36-hour window, the alert fires. The decision is still Marcus's — but the information reaches him while the window is still open. That is the entire problem being solved. Not automation, not intelligence: reliable surveillance of prices he cannot watch manually across 150 active SKUs at three retailers simultaneously.

PriceTrail is not built to replace Keepa and does not try to. It does not track BSR, does not surface ASIN-level marketplace data, and does not carry years of Amazon price history. Resellers who get the most from it use Keepa for what Keepa does best — evaluating sell-side conviction on an Amazon listing — and use cross-retailer price tracking to answer the buy-side question at the same time. The tools cover different ground. Together, they close the full loop that retail arbitrage actually requires you to close.

If you're looking for a Keepa alternative that handles what Keepa genuinely cannot — not a better Keepa, but buy-side price history across the retailers where you actually source — start tracking for free. No credit card required to add your first product and pull its price history. If you want to see how the two tools compare feature by feature, that breakdown is here.