See if Amazon or eBay is
the cheapest — before you buy
WEM stays out of your way until you open a product page on Amazon or eBay UK — then it checks for the same item across the retailers it covers and tells you if it’s cheaper elsewhere.
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 or Edge in one click, then pin it. No account, no sign-up, no setup screen.
Shop exactly as you do now
It stays completely dormant until you open a product page on Amazon or eBay UK. It never runs anywhere else.
See cheaper prices on the page
WEM checks the same item across the retailers it covers and shows a small panel beside the buy box — with a savings banner only when something is genuinely cheaper.
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.
Where it works
Activates on Amazon and eBay UK product pages, then compares against the retailers WEM covers — with more added as new partnerships go live:
Exactly what it can access
These are the only two permissions in the extension manifest. No broad browsing-history access, ever.
activeTabReads the product title on the Amazon/eBay tab you’re actively viewing, so we can search for the same item. Nothing in the background.
storageStores a single randomly-generated ID and a short price cache on your device. No name, email, IP or browsing history.
Full detail in our privacy policy.
No catch
- Dormant until you shop — only activates on Amazon & eBay product pages.
- Free. No account, no sign-up, no personal data required to use it.
- Only speaks up when there’s a real saving — no constant pop-ups.
- Affiliate links are disclosed, and your price stays the same.
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 — that comes from the retailer’s marketing budget and never changes the price you pay.
Does it track my browsing?
No. The extension is dormant everywhere except Amazon and eBay product pages, and even there it only reads the product title to look up the same item. It asks for two permissions — activeTab and storage — and nothing else.
Which sites does it work on?
Amazon (.co.uk and .com) and eBay (.co.uk and .com) product pages. It looks up the same item across the retailers WEM covers via the price API and flags a cheaper one when it finds it. We add retailers as new partnerships go live.
Does it slow down my shopping?
No. It only runs on a product page, shows a compact panel beside the buy box, and stays out of the way unless there’s a genuinely cheaper price to flag.
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.
Stop overpaying on Amazon & eBay
Free, takes 10 seconds to install, and only speaks up when there’s a real saving.
Prefer to look first? View the listing on the Chrome Web Store