I was thinking of getting a buyable 99 that is kind of worth it and eventually make some cash from it at 90-99 or so

 

I just got 35-90 cooking with wines (spent 9m) and did 90-99 with karambwans (12m income) so total profit for a pretty fast 99 was 3M.

 

Maybe Herblore? but every single pot is not profitable atm.. (osbuddy efficiency)

Any ideas?

Smithing blast furnace.

Fletching, magics (Low profit)

Herblore, I don't think that will ever be profit able.

Crafting, no.

Firemaking, no.

 

its rather easy to make profit with herblore ( making finished potions at least ) you just have to camp g.e. and find the potions that make profit before its updated on osbuddy efficiency because that site isn't instant unlike g.e. 

99 firemaking so you can charge to light normal logs by barbarian village for the trout noobs

I'd go with magic