Forget about the roof mount for two reasons:
1) That will "break the bank".
2) If you park under tree cover, you won't have TV.
If you want an automatic solution, buy the VuCube
. Note that this will only deliver standard-def TV (not HD).
If you want more flexibility and lower cost, you can buy a satellite dish and tripod on eBay or Craig's List for <$100 and just learn to aim it yourself. Many of us do.
Either way, if you have a smartphone, you'll want to get a "satellite finder" app such as "Dish Pointer AR" or "Satellite AR" to help you in the process.
What receiver model do you plan to take from home?