What should Profit on?

So i have about 10 mill and im thinking of making a lil bit more money by making profits on the G.E. Im currently F2P. Anyone have any suggestions?

 

Hey Sim.
Rune-Tips.net has good merch guides for that sort of thing.
You could also try buying rune items low and selling them high; it can work well, because people who just got 40 defence usually buy it for max, and people who just got 60 defence usually sell it for lowest.
Of course, p2p is always the best choice if you want to be a successful merchanter.