It feels pretty miserable to rent a car via Priceline or Hotwire and have the price go down by half just before your trip.
The best car rental prices are for tomorrow, in my experience. I book the cheapest I can find, then I keep watching, daily, and I book a car for the best price, almost always, the day before we leave. We have paid outrageous car rental prices for Tampa once. I looked every day, and the price never went down. I think we paid $450 for two weeks, and we have never paid that much. It was for a full-size car, so we could have a car seat for our granddaughter between two skinny adults.
Minivans are way too expensve. Don't get a minivan, if you can possibly help it. Two mid-size cars are a better option, if you have two able and confident drivers for a group.
We just booked two weeks Orlando mid-size for $154 with all taxes included. This deal was through Costco for Alamo. Alamo is Rick's choice for car rental company. We have never had a problem with Alamo (our kids have), but we have the Costco-Amex insurance, which adds $24.95 to the car rental. I would love to see Alamo try to get that insurance to pay for some ding they claim we did.
We would be honest, if a car was damaged while in our care, and knock on wood, never have we damaged a car. We pay the insurance so we don't have to worry.
To use Costco's site and actually reserve a car, you MUST be a Costco member. That's new.