Unless you are running music off hard drive, or carry a satellite service that will send you title and artist data, there's no need to get a deluxe device.
You can get the Innovonics Model 702 low-end RDS generator for around $350
It will display call sign, and has new software that will apparently allow you to switch between several static messages.
The unit is programmed by computer using the USB port. You then take it out to the transmitter. It is a little box that can sit on top of another unit, it is pwoered by a wall-wart. You bridge it across the composite feed from the stereo generator or STL then feed the output into an SCA input of the exciter. The unit uses the 19 khz pilot to generate the subcarrier (3 X 19 = 57).