Typing a store name plus "coupon code" into a search engine before checkout is slow and often turns up expired codes. A coupon finder extension sits in the toolbar, detects when you land on a supported store's checkout and tries known codes for you, applying the best one it finds automatically.
How a coupon code extension for Chrome works
Most coupon extensions maintain a list of codes for popular stores and check your cart's page against that list. When you reach checkout, the extension pops up, tests each code in the box and keeps whichever one gives the biggest discount. Some also flag cashback offers for the same store.
Using a coupon finder for a specific store like Shein
A general coupon extension covers many stores at once, including large retailers such as Shein, but coverage varies by store and region. If codes fail to apply, check the store's own promotions page, since flash sales and app-only codes are not always picked up by browser extensions.
What to check before installing a coupon extension
Coupon extensions typically need permission to read and change data on shopping sites so they can enter codes at checkout. Review that the extension is limited to checkout-related activity, read its privacy policy for how it handles your browsing and cart data, and avoid any that ask for broader access than that.