Are you looking to level attack / str or defence pure, It takes somewhere around 500 hours to get from lv 1 defence to level 75 doing monks with no other leves. The max xp you can get (even with 37 thieving so you can use a black jack as a weapon because it s better then iron) you only get about 2-3k an hour xp. you gonna be looking at easily over 100$