Every supplier on Northbound requires a credit card to cover the excess amount.
(*Please note that debit card or cash deposit are not accepted for this).
Once you return the vehicle you'll get that money returned if there are no issues with the vehicle.
Most suppliers only take an imprint of it when you arrive and don't actually withhold any amount from the card.
If you select a vehicle you can click the Important Information tab to see more info about that supplier's policies.