I'm afraid that car rental deposit fees are pretty standard across the board between car rental companies.
Your best bet is to check our information about the policies regarding Car Rental Deposits for various companies, in order to determine which company will be the cheapest for you.
The security fee (or car rental deposit) is often determined by the amount of the rental, whether or not you're using a debit card vs a credit card and which country you're renting in.
As you've probably seen by doing
some checking, the difference in the hold amount doesn't vary by much from company to company.
If the cost of your rental is $400 or more, than the hold will be at least that.... but if the cost of your rental is under $200, than there may be some difference in the deposit that will be held... depending on the particular provider that you choose.