Not sure what it costs to do the patches, as I got it done with several other alterations, too.
As for if your tailor has patches, no clue. Again, I provided the fabric, so that wasn’t an issue. Might be worth it to give your guy a call and see what’s up. Either way, finding patches/material isn’t hard on eBay and I’m pretty sure it’s an easy thing for them to do and they’ve probably done it before.