I’ve never worn a pair of jeans in my life, however I am aware that they are one of the most common articles of clothing not only in the UK but I imagine elsewhere. In fact, I find myself frequently frustrated at how easily one can pick up a pair of denim trousers compared to khakis. That said, here is a small article from the guardian website related about fair-trade jeans.
Another (semi) related article that also may be of interest to jean fans.
If you come across a documentary called China Blue, that’s well worth your time too. It was filmed, partly in secret, in a Chinese jeans factory. It has since been banned in China. If you don’t think there’s any need for Fairtrade jeans, it may change your mind. Here’s the opening two minutes:
The Earthbound Report 
How have you never worn jeans? That’s crazy.
I am sure you wore jeans as a little boy. I believe I put them on you myself. Anyway, the price of Fair trade jeans is pretty horrendous – beyond my pocket, unfortunately. But here is another supplier of Fair trade clothing that you may wish to research: http://www.bishopstontrading.co.uk/common/index.php They also sell Fair Trade fabric by the metre. Now there’s a thought…
I’ve found the same problem, that many of the ethical brands are prohibitively expensive. I still resort to charity shops and sales, and just plain old buying less.