You should be able to acquire piano rolls for about $1-$5 per title at estate sales, indoor flea markets, etc. New ones cost more like $15-$20 each.
The titles that fetch the highest prices on the resale market are newer-vintage QRS rolls. They are also the best as they adapted a lot of pop songs from the 1950s-1990s for piano roll. Also considered valuable are reproducing rolls for AMPICO, Duo-Art, and Welte-Mignon, but those rolls are of no use unless you have a compatible player piano.
Anything else besides these is going to be cheap and readily available.
There are also lots of eBay auctions for piano rolls, if you don't find any in your local market. If your player isn't working, I'd say to just get a few cheap old rolls that are still intact and hang onto them to test your piano. Then, once you are enjoying your restored player piano, you'll probably want to get as many QRSs as you can get your hands on.