If you don't mind a little work, I'd suggest getting a cheap build it yourself tuner kit and a 5W amplifier to go with that, capable of transmitting a few MHz below the FM band. Then get a cheap walkman or similar, open it up and find the tuning capacitor and also place that some below the FM band.
That way you will atleast not disturb any commercial station... Just watch it so you don't touch the police/military frequencies

// Jonathan