The eBay page you want is at
http://listings.ebay.co.uk/pool2/pli...x.html?from=R0
Personally I use the £90 Magellan 300 (I think it may now have been replaced by a slightly more modern model) which is designed for walkers. It's not so far as I can tell speed limited (at least I've used it up to 200 kn quite happily), has a clear display, capacity to put in enough waypoints for my standard routes, and runs for about 18 hours on two AA batteries.
It isn't a pilot GPS, and has more lag than aviation units - i.e. it takes a little longer to settle on a speed and heading, but otherwise I'm very happy with it.
G