Amazon and other gift cards have been discontinued some 16 months ago.
Some more facts and observations:
1) WGT Virtual Tour pays out a lot - 200,000 to 1,000,000 crs per tournament, the winner taking 18%!
2) Credits have no monetary value - see T&Cs. There are no Dollars in the game! The earning leader's list has been misleading players and unexpecting visitors since day one.
3) As of the beginning of 2013, the potential real world pay-outs have been minimized (see above), apparently with the intention to conform to some very restrictive gambling laws.