Maybe try Kastel Brothers in St Mike's. They work on inboard underwater gear and are reputable. I'm assuming they can do outboard props too.
Millers island Propeller in Balt is good, fast, and cheap.
Black Dog props in Kent island does beautiful work but are probably the priciest.
Deckleman's/Long Cove Marina in Rock Hall should be able to do it too and they are a Pwertech dealer who is having a sale.
As for cost- I have an inboard with a 22x24 prop. I bent the hell out of it and Black dog fixed it for $400. I replaced it for $2200 once and I repaired it at Millers for less than $100 once. Gotta love living in the northern bay with the conawingo dam just far enough north that the logs have just enough time to barely submerge before getting to Tolchester.
Hope this helps. Know it's a lot of info, maybe the decision is made by who can get you back on the water fastest???