I use a couple of washers that fit just inside the thread spool and it keeps the spools in place just fine. I agree that they charge way to much for simple things no matter what it's for. Most of the time, if you need something, you can just go hang out in the hardware store for a while and find everything you need to make your own stuff and far less then what you pay if it's sold for what you want it for.
And that's exactly why we are in a recession because there are so many greedy people out there. I don't mind paying a buck of something worth a buck but it's a cold day in Hell before I pay 20 bucks for something I can make under 1 buck.