I will give 20 USD to the winner.
Terms:
The challenge finishes on July 31, 2015.
Only 1 prediction per person is allowed.
Prediction must be made in USD (not in BTC).
The reference price of XST will be the one shown on https://chainz.cryptoid.info/xst/#
The one who guesses the nearest to the price will win.
Minimum number of participants must be 10.
Good Luck !

P.S. From this 20 USD half (10 USD) is donated by BTCwriter - StealthCoin supporter from the beginning.