The purpose of those "savings" and "membership" cards, which are pushed at all of the crap conglomerate chain stores, are used for data mining. They $ell the info to every damned outfit out there. This is why cashiers push them so aggressively - if they don't meet the "quota", their hours get gut. People still gladly give all their information to "save" on items which are marked up 75+% believing they are "saving" on only a 60% markup price, and to be spammed with emails.