There is really no quick way - in any case it will take a long, long time.
In any case, it works faster if you are willing to spend a lot of money. I am talking about many millions here! In that case, you can buy lots of the highest-level runes that work at your level (for example, at higher levels, death runes), and attack a lot. You might also repeatedly teleport, or do high alchemy. But in any case you lose money.
If you don't have that much money, you might try one of the following; each of these alternatives is much slower:
99 costs about 25-35m through alching. There are cheaper ways but more complex and harder. I recommend Plank Making spell (Lunar). You can sometimes profit and you lose very little per make. Either way, magic is a sorta-expensive skill to train. But in the long run, its worth it. When you get 99, got to wildy with Ice barrage. Make mills off of that so it pays off =)
There are several ways to actually make money while training magic. Members can use the Mage Training Arena, and get good money while they train. Also, if you do high alchemy on certain members-only items, you can actually earn money - for example, onyx bolt (e). Non-members have less options; you can play Fist of Guthix and get free magic experience (if you decide to attack with magic), but this is a fairly slow way to advance in magic.
There is really no quick way - in any case it will take a long, long time.
In any case, it works faster if you are willing to spend a lot of money. I am talking about many millions here! In that case, you can buy lots of the highest-level runes that work at your level (for example, at higher levels, death runes), and attack a lot. You might also repeatedly teleport, or do high alchemy. But in any case you lose money.
If you don't have that much money, you might try one of the following; each of these alternatives is much slower:
Costs 10m using the mage arena.
Cost about 30m from 80 - 99
Alching. Try to find an item that alchs for more than their value price.
charging air orbs you will accuatlly make around 400k per 1k orbs
Creating oak dungeon doors using Stealing Creation hammers
Burn maple logs once you are able to....then keep doing that to 99. This is the cheapest way to get 99 FM if you feel like spending alot of money then use higher ranked logs.
lvl 70 wc buy a ton of runes
Same as for level 99 in any other skill. About 13 millions.
Years.
A Magic cape can be purchased for 99,000 coins from Robe Store Owner at the Wizards' Guild by players who have achieved level 99 Magic.
I'm 99 wc and I like to chop magic trees, I make around 140k per hr.
99 strength and 99 magic would make a good pure. I'm not gonna lie but that would be pretty awful, unless you had 99 range too, you'd be great. Ice barrage, K0 with dark bow. ^^
Look up a magic calculator, then how many times you have to plank-make from 86-99 magic, then add the prices of the planks + runes to cast the spell together, to get the cost.
You go to your spellbook and select "enable defensive casting" on the bottom. Then, do magic in combat, not High Alch or Teles or anything.