Magic is an incredibly expensive yet necessary skill in Runescape. To learn some better ways to raise this pricey skill, read on.
From Level One, To Get You To Level 17
If you've just begun to work on mage, you'll know that its no easy feat. So, for starters, go to the Grand Exchange in Varrock or your local rune shop, have a spare 6.5-7k on hand, and buy 500 mind runes. Do not buy any more runes than this. Use your remaining money to buy an air staff. Wield the air staff, set your spell on “wind strike”, and head down to the Lumbridge cow fields and kill some cows. Make sure to take all of the cowhides and sell them for 100gp ea to a player or to the Grand Exchange. Here is something important to remember: for levels 1-17, only use wind strike. This spell gives you the most for the amount of money that you are paying for it. Cast all 500 mind runes. You should be at least level 17-18 mage by now, depending on what level mage you started at, and this should only take 45 minutes to an hour and 15 minutes. Congratulations!
From Level 17, To Get You To 30
Go to the Grand Exchange, or any local rune shop, and have around 10k+ spare money handy. Buy 500 mind runes again, but this time either buy 1500 fire runes or 1000 air runes (whichever one is cheaper, air runes are pricey but you need less of them ad fire runes are cheap but you need more of them) and if you bought the air runes, buy a fire staff and wield it. If you bought fire runes, like I did, use your old air staff and wield it. Yes, you will be using “fire strike” now, so set your staff to it. I know you can cast spells like wind bolt, with chaos runes, but at this point you only get one more exp point than fire strike if you use wind bolt, so it's a giant waste of your cash to buy any chaos rune spells right now. Trust me; Fire Strike is an OK spell.
I was using Fire Strike and a guy next to me was using Earth Bolt with a higher mage level than me, and he was hitting the same or worse hitpoints than me. This time, we're heading over to the Wizard's Tower. Climb up the stairs to the very top and go in the room with the lesser demon behind the fence. Because you can attack the lesser demon and not get attacked back, you can train here until you run out of mind runes. If there are more than 2 other people attacking the demon with you, go to a different world. When you use all of your mind runes, if you do not have level 30 mage yet, do the quest Witch's Potion or Imp Catcher for some easy XP. Congratulations! You just got to level 30 mage!