Go to a fabric store and buy a yard of Nylon/Poly strapping. Buy the widest and finest weave they have usually 2 inches. Should cost less than 5 bucks. Loop it around a towel bar or get a D ring and a couple of rivets if you want to get fancy.

It will be almost cut proof and will give you an edge equivalent to leather until you learn to strop. Once you graduate to leather, month or two you can paste the nylon.

Keep the spine on the strop and go slow and pay attention at the flip.