Sarah:
If you're only looking for web space (and don't require things like support for FrontPage Extensions or statistical analysis) the easiest place to put your site is on the servers of www.webtribe.net. Signing up is a doddle (and free!) - just your name (real or false) plus your choice of username and password. You're theoretically signing up for a dial-up account + e-mail + (free) webspace but you don't have to use the bits you don't want (except for uploading your site - see below).
You can sign-up as many times as you like (so you can have multiple accounts) and I've never come across any limits on the amount of webspace you can use. Commercial sites are welcome.
The only cost in putting your website online is when you upload. This is because the webtribe ftp server only permits connection via the dial-up service. Upload speeds are fairly slow but typical phone bill charges (based on a BT line, off-peak) work out at approx �1 per 10Mb upload).
I've put all sorts of things on webtribe's servers in the past - often things which only need to be there for a short while (e.g. details of different sports or community events - that's where multiple accounts come in handy). The most recent site I put up is full of galleries of old school photos. It will not be of any interest to you and it's certainly not a good example of web design (I cobbled it together in about 15 minutes!) but it might give you a guide to how much web space you can get for about �2.50 added to your phone bill. (i.e. about 25Mb). If so, check out www.webtribe.net/~yewlandspast. (There's an e-mail link on that page if you want to ask me any questions)
Having written all of that lot, perhaps I ought to remind you that most ISP's include some webspace with both dial-up and broadband accounts. Perhaps your own ISP has already allocated some free space for you to use?
Chris