Hmmm, this is a great question, graphicsapathy.
Generally speaking, the down payment due to JUMP! is the same as it would be to initiate a regular EIP; and there's not a way to roll it into the financing agreement -- you'd need to settle that amount due, plus the full taxes on the MSRP, up front. The benefit of JUMP! is that when you return that V20 in good condition, the remaining 12 months of EIP payments are wiped clean -- JUMP! insures you don't take a depreciation loss on the trade-in value of the phone.
Your best bet is to walk through the process with a team with account access so that we can let you know what type of up front costs you'd be looking at. I have to say, if you've had this device for 12 months already, even if you started as a customer with "average credit", if you've paid all of your bills on or before their due date (though payment arrangements don't count here), you may not have "average credit" as far as we're concerned! We use a process called Smartphone Equality to determine credit standing so that customers with great payment history and tenure can be rewarded with lower up front costs over time.
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