I booked a car online weeks before my trip, including prepayment. Upon arrival the rental car company required I have my insurance card (even though I purchased their insurance) and $400 deposit on a credit card!
That would have been great info to have up front. I was 1/2 way across the US and didn't bring a card with that much on it. I was left stranded without a car, had to shuttle back to the airport and then rent a car at 3x the cost, because it was a "walk up."
Here is the only info provided from Priceline on my booking confirmation,
"Important Information
The driver must present a valid driver's license at the counter and a credit card in his/her name. Additional drivers may be added at the counter for a fee. Additional charges may apply if you pick-up or drop-off the car at a different date, time, or location than your reservation."