Well you got 53 magic right now, I'd say spend money on getting 55 magic then alchemy yew or magic longs by trading people supplies for longs, this way you won't lose alot of money, I am not sure how far it will get you with only 500k but you should get a decent level from it. Another way od leveling magic with out runes or cash is PC, get 100 points and cash in for magic exp, with 100 points you get a bonus then doing 100 by them selfs.