I think that even though you're requiring payment, you need to show some free examples of code that you have written. You have to make people think "wow...that's really well-written code" before they'll hand you just anything to work on.

One of the most important things to me when delegating a task to a programmer is trust. I wouldn't ask just anyone to solve just any problem, so you should demonstrate to potential customers the kinds of things that they can ask of you.