The famous argos has a belkin for sale for £29.95 at the moment (
Buy Belkin Wireless G+ Router. at Argos.co.uk - Your Online Shop for .). It is the same model I have been running for years with no problems whatsoever - highly stable in my experience and at 4 1/2 stars out of 5 from 36 reviews most would aggree it seems.
It has easy to configure settings (as usual by web interface). It is only 802.11g (though I think with a firmware upgrade can be upgraded to N) but 802.11N seems to have very little compatibility between vendors from my experience.
For your home users you have the wireless connection and 4 wired connections. A built in firewall will afford some protection and it has all the usual options of port forwarding etc should you need. It is an ADSL2+ device so will work right up to the 24mbps providers that are around at the moment.
Hope this helps.