I will open a small voting here. The thing is, the way we pay teamspeak now is not the best. One month is 11,5 USD, but here is the following info about if you pay more at once:
3 months - 10% off 6 months - 20% off 12 months - 40% off 24 months - 50% off
Basically, paying more is better. That is why, I'm thinking of paying around this winter a 12 month bulk. Use the vote function to decide what you would like.