Two extremely cheap solutions:
1. (If you fancy using non-leather material): Buy a pair of shoelace, get the thick ones. Then cut the length according your length. Then burn the edges. Use a normal loop and you're done. That's what I did for my LX5* (max time 2-3 minutes)
2. If you (any of family members) have old & unused leather bag, simply cut appropriate length with a strong scissors. Obviously, you'll need to buy one/two rings, some strong nylon and a sewing needle for leather. Shouldn't take more than 15-20 minutes.