TBH, Slayer isn't a good way to make money. It is slow to train, takes ages to get to at least 80+. But even at 80 Slayer it is still awful cash, as the dragon boot release has destroyed Rune Boot prices. So it's good at 85, huh? No. Not anymore, sadly. The first whip slayer drop I got, it sold for 5.3M. Now its 1.4M. -.- The bad thing is that ALL slayer drops are...dropping (in price). Slayer is only good for having fun slaying monsters, and gaining total levels (although very slow to level). So if you want the cash, head off in another direction. Aviansies would probably be better money than Abyssal Demons now. But if you just want to train Slayer, then go ahead :P