Although we don't allow blogs with the primary purpose of driving traffic to affiliate programs and get-rich-quick schemes, that doesn't mean that all ecommerce is banned from WordPress. Many artists, writers, and other original content producers have set up great blogs to share and sell their work.
WordPress is not designed to be a fully operational ecommerce site, but we do provide a way to insert a PayPal button into your site. You can find instructions for that at:
Good luck with your site, please let me know if I can answer any more questions for you.