I've been using AskGeo for about 10 months and am very happy with it. Does exactly what I need. I am surprised to see it's now $200/year.

What I signed up AskGeo said:

Is this free?

  Yes, for now. We built this for internal use and this site doesn't cost 
  us much, so we don't intend to charge unless usage takes off. If we do 
  charge, it will be to cover costs, not because we think we're going to 
  make it big selling access to a lat/lon to time zone API. So for now it 
  is free and it is likely to remain so for a long while.

The pricing change has not been communicated to existing users, I was not aware of it until this story had been posted. I'm not sure if they get grandfathered or not. I'm doing about 1 request a day, $200 seems expensive.