cyber_electrons, on 08 March 2009 - 02:58 PM, said:
I found a way to make money by picking up free and readily available items a long time ago. I invest in potatoes.
I pick up potatoes in the farm and store them in the bank. That's 28 potatoes every visit to the bank.I usually collect until I have got around 800 and go to GE (grand exchange) to sell them. Potatoes worth around 86gp a few months back. So I would make around 50k to 70k each visit to GE when I have around 800 potatoes.
I also kill cows as the raw meat worths quite a lot and expecially the cow hide which I beleive worths around 102gp. Chicken is also my popular choice as they are easily killed and the raw chicken also worth quite a lot.
Post your ideas and investment plans here!

I'm big into merchant style investment. I'm not really big into the game very much right now, but I set up a Microsoft Excel spreadsheet, and I've put all of my investments there to see how much I've made and what not. The way I make money is by buying up HUGE quantities of items which I think are currently undervalued, and wait for their value to rise. Think stock exchange, not grand exchange. For instance In the past week I started with an initial investment of 6,942,000 and I have made 188,000 based entirely off market change. It literally took about 45 minutes (maybe even less) of research time, then 5 minutes to buy.
Maybe you don't have those types of resources for investing, but you can still do the same thing. For instance if you invested 69,420 when I did, right now you would have 1,880gp without ever having done any actual work.
Sken-d investment
PS I would look at buying iron ore, clay, and raw lobster right now.