I played with it through the T-Mobile app today. The prices don't seem worth saving the $35 charging fee. I just looked at a DEN trip I was looking at for end of the month.
AAA rate:
Small electric SUV:$334
Int Electric Elite: $362
Tesla Standard Range:$524
T-Mobile EV rate:
Small electric SUV: $416
Int Electric Elite: $587 (this seems weirdly off. I keep looking at my screen shots and it seems crazy to be that different but I am half asleep)
Tesla Standard range:$616
Someone else should play with some reservations but this seems like a horrible deal.