I just hope they don't have "levels" of paid accounts based on followers for example. A single $20-$50 per year would make sense to me. But I imagine whichever route they choose, and no matter what cost, they'll sell anyway.
I think the key part of it is the "verified" part of the deal.
#1 rule of startup pricing: CHARGE MORE.
For the value that Twitter Business Accounts will provide to businesses, a basic fee of hundred of dollars per month sounds reasonable, and then added features could cost extra. I know I would pay if I were a Dell or a JetBlue.
Given the breadth of different companies I know have been involved with Twitter (from small local restuarants to boutique culinary appliance manufacturers to Comcast), there must be thousands of companies who would pay for this service, especially if Twitter can lower the barrier to entry for them and provide metrics so that company Twitter advocates can gin up some kind of ROI.
