I hope you stick with the game, I made most of my money in the game not with DEC or SPS but rather with the cards themselves. I use my DEC winnings to buy up cheap gold foil cards, and play for the long game. When prices spike GF cards recover thier prices first. thats when you can take your profits. But you have to play more as an investement rather then daily rewards to cash out.
I wish you luck on your GF !