For inexpensive with plenty of features, space, and unlimited bandwidth, HostMedia.
If disk space is really unimportant, they do a single site 100MB space package for a £1 setup fee, but otherwise it's starting at £24/yr for 5GB+ space. (But search for cfhour podcast and there's a discount code that may or not still give 50% off every year.)
Dealing with HostMedia support can be frustrating - sometimes stuff stops working (probably because they've fiddled) and their first line support don't read messages properly and can give spurious explanations of fixes - but they're probably not the worst I've dealt with, and I think they are the cheapest.
That's all assuming you're after simple shared hosting, which should be fine for regular link sharing and casual commenting - I'd expect an average much lower than a request per second per user, so upto 20 online users wouldn't be much for a decent server - but if there's heavy chatting and media uploading then performance could be more impacted by how many other customers the host has put on the same server.