You can profit from mining your own ores.

I did use the blast furnace a bit on my old account, but just how effeciant is that? or is there a special world now where people accually run the thing together?

Smithing exp with a nice tidy profit is iron knives.

 

But 99 Smithing can cost 0gp-100M, it's all about what method you use. Buying Addy bars and making bolts is a small loss, but after a while it will add up. Buying iron bars and smithing into plates is faster, but unfortunately more expensive. But the most expensive way for fast xp is to buy steel bars and make steel platebodies and then alch them.