buying pcs on bias room

hi everyone! i’m new to this app and im looking for some advice, i normally only get my cards off of mercari, so i’m a little skeptical and scared of getting scammed on here but someone is selling a card i’ve wanted for a while so i'm super interested. does anyone have any quick tips or red flags to look out for? thanks so much! (i’m also curious how do transactions work on this app? )