I made a flogger from a keyring, a roll of leather string and black duct tape. It looks great, I made it more than ten years ago and I've used it plenty and it's still works fine.

All in all it took me about five minutes to make and was a great investment.

edit: I wouldn't try to cut up strips of the belt yourself. It's hard to get it straight even with specialised tools. Buy leather string on rolls.