Ebay; one of the worlds most common websites.
Don't trust sellers from there if you are buying designer products! Many lie and say they are authentic, but they are not!
seller: i promise you this louis vuitton alma bag is 100% authentic or your money back!
buyer: yay that's cool! *orders it and spends $1500*
buyer: (recieves package and purse)
buyers friend: ewwwww your purse is a FAAAKEEEEE!!
buyer: no its 100% authentic!!
buyers friend: no its not hun. i know what replicas and knockoffs of louis vuitton look like. you have one.
buyer: but i spend almost $2000 on a fake purse!!!!! and they promised it was real!!
buyer: (goes back to ebay, sends seller an email)
seller: (reads email and deletes) (laughs his head off because he ripped her off)
buyer: *cries for years*