Need stand-up proof holder...where to buy

I did a senior shoot as a favor for a friend. They want to order one of the proof holders that you can stand up for display. I think they hold like 3x5 or 4x6 size proof pics. Any one know where I can find one of these? All I have been able to find are proof albums. Thanks in advance for any help!

Sounds like a cheap way around buying prints.

She is buying a lot of prints from wallets to very big ones. I think he saw a friends and wanted one too (the friend got it from the professional photog place that does all the tux/drape pics for the school). They get all their edited proofs free with a certain purchase amount and are going over that amount. They just wanted this as a way to display their favorites so that you can see them all, instead of in an album. I got one with my senior package too but that's been about 11 years ago.