When I have free time I check monster market to see if there are any good trading opportunities available. Sometimes people sell beta 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. I wouldn't recommend to do it because I think that the monster market don't have enough liquidity as before. Also with the addition of rental market people can now rent maxed out cards for super cheap instead of buying lots of cards on the market.
