Most rental providers do require a deposit for security reasons. If you choose Full Coverage with Discover Cars, the deductible for your rental car will be covered, but you will still be expected to leave the full deposit when you pick up the car. 

Information about the exact amount of the deposit will usually be stated during the booking process and on your Voucher. The deposit amount depends on the type of car that you choose, the country you travel in, and the rental company you select.