I just went and pre-ordered at Radioshack. Last I checked my credit score was low 500s, I have no phone payment history since my iPhone is in my dad's name. I have 4 years of car payments with only one or two 30 day lapses for the entirety of the loan, and about 2k in delinquent debt from 6 years back. They "approved me" for the super low deposit of 250$. It's more than I expected since last time I tried to get a smartphone in my own name the deposit was 175$ with Verizon, but that was back when the Palm Treo 700w was released.
So I'm gonna be getting the phone a 200$ with a 250$ deposit which I will get back in 12 months of good payments, though I'm unsure if I will get a check or get credits on my bill. A sprint store could probably start the process, but they CAN'T PREORDER THE EVO, Radioshack can, however, and do the credit check/pre-evaluation for you. I highly doubt your fee will be higher than mine. Best Buy should be able to do the same. Be aware if you buy the phone with cash it will cost an additional 8$ to make the deposit. Apparently that is a cost on Sprint's end that the retailer will pass on to you, a credit card avoids this. I was assured that a Visa Check card avoids this fee as well.