I have used the pre-paid expedia.ca offer before in Phoenix AZ (last year 12 day rental). I actually called expedia after I made the booking because I was concerned that I was duped. They confirmed that everything other than Insurance (which was optional) was covered. There was no extra charges ... hence, I booked this again for 2012 in Phoenix ... 14 days!
The only downfall of this is that this is pre-paid, and that it does not have the flexibility of say Port canaveral to WDW as a rental option. These deals revolve around airports.
Ted