Budget:

they process a credit card hold of total estimated charges plus 25% or $200, whichever is greater. so they have a $200 minimum hold (this minimum hold would only occur if your rental total was under $160). With a rental of 5 days (assuming the total is over $160), just mulitply the amount of the rental costs by 1.25 which will give you the amount of the car rental deposit required.

Dollar:

They place a hold on a credit card of the total estmated rental charges + 15% or a minimum hold.. again, whichever is greater. They stated that their minimum holds range between $250-$300 depending on the specific location that you rent from. They suggested contacting the specific city location for more details on their particular policy regarding credit card hold.

other, not so specific responses I received, included:

Enterprise:

They referred me to their website which states:

The actual deposit amount can vary based on the approximated total cost of your rental. This cost is based on the size of the vehicle you are going to rent and how long you would like to have the vehicle.

A good rule of thumb is the cost of your rental plus an additional amount. If you need to know an exact amount to plan for, our reservation center can help you with these details for most locations or you can contact the renting branch.

Alamo, Avis,Hertz National and Thrifty gave no specifics as far as car rental deposit or the hold on a credit card. All reps from these companies stated that the deposit amount can vary by your age, car type and location and suggested that you contact a location for the specific city or town that you would be interested in renting in, for more details. All companies did tell me though, that a cash deposit requires a much larger deposit than when you do the hold on a credit card.

Hope this helps!