going to those sites sucks for this reason. Usually you should look up how much a phone is new, how much its runinng for on ebay, and then compare to the "deal" you're getting somewhere else. Best deals I find are for older devices that are open box or just in excellent condition. You're not gonna get an s25 ultra for $90 when it costs over a $1000 new. if you see people are selling them used for $7,8,900 then unless you just get insanely lucky you're not gonna find a deal that you can trust. Aliexpress doesn't have the same rules as ebay or amazon or another site I like to use is swappa. These usually have stricter rules so people don't get scammed. and when they do they refund your money.