At rap-resources.com, there are lists of radio stations (station call letters, program director’s name, address, and phone number) for $15 each. There are lists for Urban radio, Rhythmic radio, Top 40 radio, Urban AC radio, Gospel radio, and Country radio. If you need an explanation of the differences of these genres, you can find that at http://RapResources.wordpress.com where there are examples of charts posted to show you the types of artists at each.
A street rapper or underground rapper would need Urban radio.
A more commercial rapper would need Rhythmic Radio and Urban radio.
A more pop rapper or singer would need Rhythmic radio and Top 40 radio.
An R&B singer would need Urban radio and Rhythmic radio.
The lists are $15 each and available at rap-resources.com.
Click here: http://rap-resources.com/#store