You will either need to pay the Deposit, or use a Prepaid account, you will just be limited as to what you can or can not do with the phone, being that alot of the features require you to have a Data Plan. Or you can pay the deposit, build up your account with them, and maybe they will let you add on lines with out a deposit in the future.
The only other option, if you choose, would be to Jailbreak and unlock the phone, then you can use it on T-Mobile, which has a different system when trying to get approved for lines without a deposit, but there again you will be limited ont he phones functions.