Just be careful with the tribulus man, I've heard some good things and some bad but have no personal experience so I can't say for sure. That's awesome about the binder! As far as an STP they can be made cheaply out of a lot of things such as medicine spoons, coffee can lids, and other things. They won't last as long but it might be worth looking into to see if something like that would work for you.
If you're looking for a packer the Mr. Limpy from early to bed starts at $13 or something close to that. Best of luck man