Also be sure to ask your parents if you have anyone that does web design or dabbles online. Long ago I owned some for profit sites but now they are just hobby sites (that I pay for.) I can host 6 websites for the fee that I already pay so I just added the school's PTO site on to my hosting service for free.
It worked great for us. I'm the VP and the only one interested in online communications. I can access and update the website 24/7. When the PTO (which started up last year) is making $$ and I'm ready to move on, then they can find another parent (or see if a local company will sponsor the site) or pay the money to host the site later.
I bought the domain name (and just considered it a donation) and got 4 years for $19.99 by shopping around for a good deal. I'm not sure if I used Yahoo or Go Daddy but I used which ever one was cheaper the day I set it up!!
I only pay $6.95 per month to host all my sites, have tons of bandwidth, lots of free software included (for blogs, message boardes, shopping carts, etc.) and more email addresses than I will EVER use!!!
I think my next project is to start a blog page that I can use as a site update page.
www.vistacampanapto.com/
If you want to use a free site, I recommend that you go ahead and buy the domain name you want and then have the website point to your free site. Then people will type in XXXPTO.com but get to your http:really_long_and_hard_to_remember_url_website_for_pto.com/even_more_to remember.htm
A good webhosting service can walk you through how to do it. That way your URL is easy to remember and will stay the same no matter WHERE you are hosted!!!