When you put in a deposit, it is charged to your 
card (that's the whole point of a deposit), but I 
think that you have the option later to use your 
deposit *towards* whatever item you are buying.

Meaning if you put in a deposit of $100 and the 
item you buy comes to $200, then I'm pretty sure 
you have the option of using your $100 deposit 
for the item, thus you would only owe an 
additional $100 to cover the total. (But then, 
remember, you would have no deposit with them 
anymore.)

Obviously, it's best to ask them. ^_^  They're 
all really nice there, so don't be shy about 
writing! ^_^

Many Sharp Smiles,
--Drac