I would suggest wetting clay in Varrock. I have heard at the moment that is the absolute best thing you can do to make money with low requirements. I am not positive, however would assume that wetting the clay into soft clay at the fountain in Varrock East bank would be the easiest and also the most profitable. I do not remember how much the profit is, though it should be better than anything else at low level requirements. If not you could always just mine iron, it is a fairly low requirement and almost always a decent profit.