Buy and sell TEK at
https://www.cryptsy.com/markets/view/114 avoid this site for now
https://www.cryptopia.co.nz/Exchange
https://www.bitebi9.com/markets/view/TEK_CNY avoid this site for now
The reason you want multiple exchanges is if 1 or more exchanges have tech difficulty, you will still be able to trade your coins.
Also different exchanges have different coins so you have more to trade with , without suffering the withdrawal fees to other exchanges.
Current Example there are problems with cryptsy & bitebi9 , so there is only 1 trustworthy working exchange, if it had a problem , you have no where to exchange Tek.
That why there is a strong discussion about finding another exchange, so you have at least 2 working exchanges that people trust.
Redundancy provides Stability for a continuous operation like a coin network.
FYI:
Consider Yobit as a more viable option than Bittrex or Poloniex, as it will give you an exchange with 3 languages supported.
Also unlike Poloniex, New York State Residents can use Yobit.