Also available is the XM Snap In-Vehicle Radio, model no. XSN1V1, for free. Plus, receive 30 Days of XM Satellite Radio for free. Shipping adds around $8. That's another low by $39. This plugs in to your vehicle's cigarette lighter or power adapter socket.
Note: If you don't cancel before the 30-day trial ends, your credit card will automatically be subscribed to a recurring quarterly subscription plan at the current rate every three months. (This plan is currently $38.85 for three months.) See the terms and conditions for more information.
Update: Links corrected.