The ETS PSP is pretty nice, and you get a lot of high quality for the price. Plus it gives some money back to this site. There are some posts on here where people tried to create their own PSPs and spent a lot more money than they would have if they just bought Doug's kit in the first place.

That being said, you may not need everything that's in there or you can find alternatives. You can come up with different fire sources (flint, mini bic, matches), and make your own PJ Cotton balls, and I've converted hard drive platters into very effective and cheap mirrors. I think it would be interesting to see what you come up with for the lowest cost and it would certainly be an educational exercise and team building for the scouts (put them in groups of 5 to see what they come up with for alternatives, etc.).

If you buy a bunch, I'd see about getting a bulk discount from a retailer.