As long as you can pay the cost each time, you can use the same activated ability as many times as you like
Random matches pair you up with another random player somewhere in the world, but private matches are password-protected so that you only play against the other person with the password
There are a handful of ways to abuse this Saga, and its high price tag reflects that
Sacrificing five creatures sounds like a lot for a tutor, but one Fleshbag often kills three or four creatures, and Lagomos provides free sac fodder on its own, even if you cant make the tutor ability work
FromTheShire: Yeah this and Painful Quandry being in Standard means there's an actual playable 8 Rack variant (a mono-black control deck with effectively 8 copies of The Rack with the inclusion of Shrieking Affliction as its win condition) which is awesome, though the current build I've seen only runs 2 copies of Affliction to be 6 Rack in truth
The most obvious fakes have printing and color issues and are fairly easy to spot when compared to the original ones that have crisp and clear printing on them
