i want to make a new account and dont waste time.

Hey guys, i just want to ask a quick question.I want to make a new account and waste the less possible membership so should i start a new account and do all f2p quests since i'm going to do them anyway or should i buy a membership and do waterfall /gnomes.. since i am going to waste time training my combat in f2p if i want to complete all the f2p quests.