Xact's XTR3CK Sirius receiver
is a plug-and-play unit with a clever mounting option: your sun visor. The included mount can stick on the dash, the windshield, and all the other usual places but also will grip your visor and even has a switch to flip the alphanumeric display upside down so that you can read it when it's visor mounted. It uses a built-in FM transmitter that will tune to any FM frequency, which is becoming par for the course in this sector. The XTR3CK has a scrawny list price of $49.95.