MaxCircuitDirtiness (TOR)

Im not sure if this is the right thread. Just wanna know if anyone can teach me how to edit MaxCircuitDirtiness . Correct me if im wrong. Im having a problem registering on tagged because maybe my free vpns' are blocked so im planning now to subscribe to a paid vpn. I tried using tor but im still getting banned because every few minutes the ip change so if i can adjust it for long time,maybe for few hours then i dont have to pay for vpn. i have read that i just have to edit MaxCircuitDirtiness on tor but i dont really know what it is and how. cant find it on the net. can anyone explain? thanks in advance