When I have free time I check monstermarket.io to see if there are any good trading opportunities available. Sometimes people sell chaos legion and reward cards for super cheap. When I see opportunities like that l buy these cards and put them at higher prices on the market to make profit. Sometimes l make 20 percent profit sometimes more and sometimes l lose money. You can also manipulate the market by buying lots of useful same card from the market and put them on the market at higher prices to make profit.