Perch is new really small CMS created by edgeofmyseat.com. It perfectly suites simple static websites that require some text changes to be made from time to time. It costs only £35 as a one-off unrestricted license cost per domain and doesn’t require any additional monthly payments.
It’s easy to install and customize on shared hosting. All you need is PHP5 and MySQL4.1 or later.
The great thing about Perch is that it does exactly what you expect of it without any unnecessary heavy functionality.
Unfortunately they don’t provide a trial version yet but you can download a Compatibility Test Suite to be sure it’s going to work on your hosting. Very nice of them!
I recommend to have a look at their website for detailed instructions, which are nicely written by the way.