A suggestion I'm hoping some one at Ting will consider:
As I gaze upon the service options that Ting is offering; it strikes me that there seems to be something missing between the small and medium levels. For example, I'm thinking the small choices could be adjusted to allow for something like a 250 minute and 250MB choices for an additional $3. Something like that; doesn't have to be 250 but something less than 500 and more than 100 (I would say no more than 200 units) and costing no more than $3. Not sure about the texts since the jump in difference is so extreme for so little a cost in that regard.
I'm sure things will work out fine as they are, I'm just sayin' seems like there almost needs to be something between 100 and 500. Since Ting is so young, there is plenty of room to adjust into the role you are seeking to fill in the market.