Making a change purse?

[dracosangel.livejournal.com]

Hi!  I have a quick question.  I wanted to take all these Ice Mice boxes I've been saving, and make some sort of makeup bag, or chnage purse.  They're cardboard-ish, so how would I do it?  I would like it to be as "waterproof" as possible.  I mean I'm not going to carry around water in it, but I would like it to stand up, and last longer then a week.  Thanks girls!

Thats it on the bottom right.  Thanks in advance for any ideas!