preferably involving combat in a way i could make umm around 15m on a fresh char to make a pure?

15m is hard to make on a character with all of his cb stats above 80... Your best bet is to start RCing. Thats' the advice I give to everyone. I have 86 fishing and apparently I can only make about 100k an hour, that'd take me 150 hours to make 15m. There's no way for a noob to make 15m off of combat, and especially no way for a pure to ever see that kind of money from combat.

In f2p, you should do rune mysteries and start by mining rune essence or help air run for money.

Try mining your level up until you can mine iron, and then mine iron and sell it for alot of cash at falador east bank.

Guys he will never see 15m...

Its unlikely he will. Slayer tasks can get alot of cash, but he didn't say P2P or F2P