As long as there is NO ability to copy them, I believe that market forces will determine the price. If only a handful want a style, it will be expensive. But if hundreds of THOUSANDS want the style, you can sell it for a buck and make a fortune!

An iTunes Store-like interface and system might be great. Allow third party style makers to sell styles (the operator of the store takes a percentage), the best ones succeed, the weak ones fail. But if you make money off of each and every person that uses a style, rather than now you have to make a LOT off the initial buyer, because he will then give it away free to his friends (and they to theirs, and so on), you can afford to make them so cheap that EVERYBODY will buy them.

I'd happily pay $20 a month for 20 new styles, IF they were good. But I'm not sure I'd pay $20 for ONE style. No matter HOW good it is. I'd want too many more, and end up broke!