First off: There are people that will rout to a Dynamic IP. I know a few people that use it. There is software the pings the host site and it records the current IP and adjusts the pointers within seconds or minutes. If you want to lookinto this do a search for Dynamic IP's and and see what you get.
The bad thing about doing your own hosting or on your schools servers (besides the previosly mentioned BS with IT "profesionals") is ther is not the same Backup and redududnacy for your power and backbone connection. Our town talked about putting a generator in at our school because the local power gets lost if the wind blows in the wrong direction. And I'm not in the back woods either. My Cable connection is usually good for a month or two then will be out for 2-days. Can't count on that one!
I uses a company called FeaturePrice and
www.featureprice.com they also have a feew affiliates that offer different stuff. For 25/mon, I can host 6 internet sites, with tripple-redundant T3 backbones, Power backup, daily server backups, UNLIMITED Disk Space, UNLIMITED: Email; FTP; X-fer; MySQL; HTTP Streaming (because their connection is fast enough) and a bunch of other stuff. They have plans starting from 5/month if your just starting.
Be ware if things are too cheap or free- you may have to deal with ADs or Lots of Downtime or No support.
Good luck