If you play the mobile version of the game and have considered buying credits through the mobile game. Don't do it. The mobile game shows credits costing $9.99 per 1000. That would or should be a 1 cent saving per 1000.
Last night at work I bought 4000 credits in 2 2000 credits purchases. $19.99 for each purchase appearing to be a 2 cents savings. But what I was charged by Apple Game Center (I tunes) not WGT was $19.99 plus $1.20 for 6% sales tax making both purchases cost $21.19 each. I sent customer service an e-mail about this.