I'm sure there are many manufacturers and models for all budgets and operating requirements. The link I posted had about 10 different models. The reason for the link was that I was confused by the initial post because:
1. If you connect your exixting radio to the new transmitter you just built and transmit the music to the new FM receiver you just built, you are back where you started. I mean, if you are going to carry around an FM receiver, why not just carry around one that receives music instead of the lone signal from the new transmitter (like a Walkman).
2. Assuming that you want to transmit something other than radio (like a CD), then you gotta buy all the parts and invest the time for a transmitter, receiver, earphones, and battery charger. Unless you have lots of spare parts and plenty of free time, it makes lots of sense to just buy the whole thing for $50 - $60.
I have tons of parts - if I only had the free time to play with them. . .