A friend of mine accepted a number of prop blades that were for a Douglas A-26 in payment of a debt. He had no use for them and would have glady sold them. That was around 20 years ago and I do not know what happened to them and have not communicated with him in some time.
Best bet would be to look up a propeller repair service and see if they have some unserviceable and irrepairable examples they would let go cheap.