$25 a year would be too low, everyone will be verified - which is kind of counterintuitive.
One more thing, it's 2017 and if I am paying you money let me edit my tweets for a certain period after posting to correct spelling and grammar errors.
I don't believe this.
Suppose it is true. This would be an excellent reason to start with a "quota" (say 10000 per day) - sort of a queue based FIFO system.
But each day, there will also be a few (say 100) which will open up for bidding allowing you to jump the queue.
If $25 a year is really too low, then some variant of this system should work.