It's still not available in exchange because this is still a testnet.
IOST, IOTX, ZIL, THETA, ENIGMA, QLC, AE - those are only few coins out of dozens that was listed on binance, priced 60M $ - 1,2B $ while still being in testnet.
You can buy/sell IDENA on discord OTC:
https://discord.gg/UjBAmz (official discord chanel)
https://discord.gg/Vrzvkwq (OTC escrow service)
Current price ~100-250 sat.