Short answer: check three things before you buy anything, the price, the checkout, and the payment method. Fake stores almost always fail at least one.
If a product is 70 to 90 percent cheaper than everywhere else, the store is likely fake. Scammers use impossibly low prices deliberately, they create urgency and short-circuit the normal comparison shopping that would otherwise expose them. Check the same product on two or three trusted sites before assuming you've found a genuine deal.
Before entering any card details, look at the address bar. It needs to start with https:// and show a padlock icon. If it only says http://, leave immediately, your card details aren't protected on that page at all.
Search the store's name plus "scam" or "review" on Google before buying from any site you don't already recognize.
Legitimate stores accept credit cards or PayPal, both come with real buyer protection if something goes wrong. If a seller insists on bank transfer, a wire service, or crypto only, that's close to a guarantee it's a scam, since none of those can be reversed once you've sent the money.
This is one trick out of dozens. The Scam-Proof Playbook covers QR code scams, subscription traps, phishing, and more, in plain language, with real examples.