So you wen ton a big shopping spree,your read to check our and you forgot your..  

Let see... i think, if that kind of things happen to me:
I will pretend that I forgot several stuff, and then I will find some spot to call my parents or my friends or my siblings to bring me some money. Otherwise, I will put the stuff back, pretending take another.

Wow how embarassing, I have done that before but it was because I left my debt card in my car. I would just ask to put my stuff on hold and go get money...it would be crappy to have spent all that time getting the stuff you wanted together and having to put it all back!