Does anyone have a recommendation for an inexpensive FP with a decent music nib? All I've seen are the Sailor 1911s on eBay for around $80.

Any other sources?

You might be hard pressed to do better then the Sailor.

Well, they're not really music nibs, but you can try the cheap calligraphy pens with broad italic nibs. Manuscript and sheaffer makes some of that type. You can find them at some art supply stores.

I have four fountain pens with music nibs -- Sailor 1911M, Pilot Custom 74, Platinum #3776 Maestro, and the smaller Platinum Conductor. Your best best may be the Platinum Conductor. It's smaller than the Maestro, and it performs better than the Sailor 1911M. I don't know if the Pilot Conductor is still in production, however. I purchased mine from engeika on eBay. Good luck.

I have the first three: IMHO Platinum's Music is better than Sailor's.

It depends how much music writing you need to do and how fancy you want to get. Any italic nib will do the job. Music nibs are supposed to flow better, but that doesn't always turn out to be the case.

Two tines or three tines doesn't really matter, as long as the pen flows well and makes the width of line you need.