I was thinking along the lines of a generic AM (w/noise blanking & ~5kHz audio bandwidth) + FM (local/distant switch) radio, the radio could be designed to work with just 1 AA battery (and operate for a long time on this 1 battery) and be styled similar to a smartphone.
The radio station(s) & sponsor(s) logos would be printed on the packaging only, the radio could be given away nationwide by various radio stations (or related companies) and maybe sold at the various "Dollar" stores for ~$5.
IIRC, that's the whole idea of putting the complexity (of broadcasting in this case) at the broadcasting end and using a system that can have very low cost receivers, AM and FM receivers are mature tech (take what's been learned about AM and FM reception in the past >100 years, boil it down to an IC and mass produce it), this low cost receiving circuit could also be used in home audio systems, to make sure that AM and FM is included in even the least expensive home audio system.
Kirk Bayne