>> $25 a year would be too low, everyone will be verified I don't believe this. Suppose it is true. This would be an excellent reason to start with a "quota"

>> $25 a year would be too low, everyone will be verified 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.