I agree with Berserkbiship, contact cement is great stuff, but not a replacement for a rivet.

My general advice for leather or chain? Leather for day and typical informal wear. Chain for formal evening.

I have found that the biggest danger with cheap sporran straps (chain or leather) is the cheap clasps often used. They are small and sharp, and will do damage! If you get a cheap strap, I suggest replacing the clasp. Check out the following for an example of one that I did recently:
http://www.xmarksthescot.com/forum/i...505/index.html