I know this won't be helpful to you, but I'll just share the info. My budget is tight, but I wanted to have the credit charge option. I signed up for the Square and I ordered a prepaid smartphone from HSN. The phone was $149.00 but with flexplay its broken down to 3 payment of 49.85 (found a coupon code for $10.00). The phone service is $25.00 per month without any contracts (300 minutes--about 275 more than I need-- and unlimited text and web) through Virgin Mobile. This has been the lowest cost option I've been able to come up with.
I just did this so I don't have the equipment yet,hopefully it will work out, I'll have 30 days to test and if it doesn't atleast I can return the phone.