Crystals for leveling up your cards should be HALF as much. seriously. to level a rare up to level 2 costs 50k gems. That's highway robbery. EXP isn't even important with a cost like that.
I thoroughly enjoy this game and have paid $ for the "v.i.p." to support the devs. HOWEVER...This game wont go much further if you don't stop being SOO money hungry. It's difficult enough to earn in-game gems without having to spend money on light crystals, and the cash to coin ratio is outrageous. I would love to keep playing this game and supporting you guys for your hard work, but PLEASE listen to the feedback of your audience!
Just a little tip...The best way to make money is not to fish, play the casino (unless you are really lucky), or burgers. Saybox was even kind enough to put it in the title for us. Go Idle.