See if the price is
cheaper elsewhere — before you buy
Stop opening a new tab for every retailer. One click from the popup compares any shop worldwide. Automatic on Amazon, eBay and major retailers — same-currency results, without leaving the page.
No account · Minimal permissions · Your price never changes · See exactly what you’ll see
Headphones
Sony WH-1000XM5 Wireless Noise-Cancelling Headphones
£299.00
Add to basketSony WH-1000XM5 Headphones
eBay
£259.00
£40.00 less
Sony WH-1000XM5 Headphones
AliExpress
£274.99
£24.01 less
Sony WH-1000XM5 Headphones
Amazon
£289.00
£10.00 less
Price comparison by wem3.ai
The WEM panel as it appears next to the retailer’s buy box (illustrative data).
How it works
Install & pin — 10 seconds
Add it to Chrome, Edge or Firefox in one click, then pin it. No account, no sign-up, no setup screen.
Shop anywhere — compare in one click
On any product page worldwide, open the popup and tap Compare this page. Automatic widget on Amazon, eBay, Currys, Argos, John Lewis, AO, Very, Boots, ASOS and Apple.
See cheaper prices on the page
WEM checks the same item across the retailers it covers — same currency only — with a savings banner only when something is genuinely cheaper, plus match confidence and shipping cautions on cross-border rows.
Buy where it’s best
Click through to the cheaper retailer, or open the full comparison on WEM. Affiliate links are disclosed; your price is unchanged. Stack a coupon tool like Coupert at checkout if you want codes — we never inject them.
Where it works
Use Compare this page in the popup on any shop worldwide. Automatic widget on Amazon, eBay, Currys, Argos, John Lewis, AO, Very, Boots, ASOS and Apple — results from retailers WEM covers (examples below):
Exactly what it can access
Declared hosts for the automatic widget, plus activeTab/scripting only when you press Compare on another shop. No broad browsing-history access, ever.
Host access: declared retailers + wem3.aiAutomatic widget hosts include Amazon, eBay, Currys, Argos, John Lewis, AO, Very, Boots, ASOS, Apple and wem3.ai. On those product pages it reads title and price to look up the same item.
storage · alarms · activeTab · scriptingstorage keeps a random install ID and your settings on-device. activeTab + scripting power one-click compare when you press the button on another shop — only after you click. alarms batch anonymous demand events.
Full detail in our privacy policy.
No catch
- One-click compare on any shop worldwide. Automatic on Amazon, eBay and major retailers. Never rewrites the page you are on.
- Free. No account, no sign-up, no personal data required to use it.
- Only speaks up when there’s a real saving — junk matches are filtered and explained.
- Creator-safe affiliate: we earn only when you switch retailer via our link — never by hijacking inbound tags.
Questions
Is it really free?
Yes. There’s no charge, no account and no subscription. WEM earns an affiliate commission if you buy through a retailer link you chose in the compare panel — that comes from the retailer’s marketing budget and never changes the price you pay.
Will this stop me opening so many tabs to compare prices?
That is the point. Stay on the product page you are already on and see whether the same item is cheaper elsewhere. Checkout still happens on the merchant.
Does it track my browsing?
No broad history access. The automatic widget only runs on declared retailer hosts. On other sites, nothing runs until you open the popup and press Compare. We store a random ID and settings on your device — not your name or email.
Which sites does it work on?
One-click compare from the popup on any product page worldwide. Automatic widget on Amazon, eBay, Currys, Argos, John Lewis, AO, Very, Boots, ASOS and Apple. Results draw from the retailers WEM covers via the price API, with same-currency comparisons.
Does it apply coupon codes like Honey?
No — and that is intentional. WEM answers “is this cheaper elsewhere?” before checkout. Use a coupon extension such as Coupert alongside it if you want codes; the two do not conflict.
Will it work on Edge?
Yes. There’s a dedicated Edge build, and the install button routes Edge users to the right place. Edge can also install directly from the Chrome Web Store.
Will it work on Firefox?
Yes. There’s a dedicated Firefox build on addons.mozilla.org running the same version as Chrome and Edge, and the install button routes Firefox users straight to it.
Stop overpaying on the product page
Free, takes 10 seconds to install, and only speaks up when there’s a real saving. Pair it with a coupon tool if you like — we own the compare step.
Prefer to look first? View the listing on the Chrome Web Store