If you make a counterfeit card and sell it to a knowing customer, then no, you didnt cheat that customer
However, effects that stop a creature from untapping "during your untap step" or "during its controller's untap step" won't stop that creature from untapping during another player's untap step, and as such, Prop Room's ability will cause that creature to untap
The alternative is that my attacker goes unblocked, and that can either make an opponent dead or I can sacrifice the attacker myself in the post-combat main phase
I would say that approximately $50,000 to $60,000 is what I made last season
Set Boosters are available individually or in displays of 30 packs
What its not is a shortcut to sanctioned play