Bags, bags, where to get bags...

I need some bags done up before I go out to San Diego for Comic Con.... enough people come to the tables and buy something and then look around haplessly for a bag to put their item in, that I need to do something. I wonder where I can get some with a logo printed, cheap. Or maybe the way to go is just get some plain bags, and then have stickers printed and slap 'em on the bag?

Stuff to ponder.