You act like your "secret" is actually that, a secret. Its not.
You don't know my "secret."
Obviously, it's playing the market. And with that, there's certain cards I can find at a low price with ease and resell for a good profit. That's my secret. I'm not going to say what cards I buy, because then I will be competing directly with people here and that market will be saturated and no long be an efficient way of making coins.
So yes. I buy low/sell high. That is not the secret, and I will not be saying anything further.