XM Radio suggestions for 2011 Prius Two

Hey...just need some input on adding XM to my 2011 Prius Two-no nav. I just spoke with the dealer and they said I needed to purchase a receiver and fit kit- $465.00. Then $180.00 for installation. I have XM on my phone and listen to it through the AUX plug. I hate having the wires from my phone attached and the chance of getting a ticket for looking at my iPhone for the XM radio. Any suggestions on where I can find these parts cheaper? Also, is it possible to upgrade and purchase a radio with nav that would be XM ready since I will be spending the money? Would I still need to purchase a receiver with a nav unit? Thanks!!