Personally I'd steer away from the cheaper Garmins. They're so small it's ridiculous. For the money a Bendix Av8or is one of the best choices on the market.
We have a SkyMap 3 for VFR flying (£450, eBay) and frankly it stomps all over the Garmins, although if you're hiring and need to constantly remove it from the aircraft it might be a touch on the large side.
I don't have a particular problem with Garmin - I'm in the verge of buying a stack of their stuff for my panel, just that their low-end products are pants.
If you're really scraping the barrel money-wise, as mentioned you can get a cheapo car job running Windows CE (Crap Edition), put memory map on it and buy the CAA charts. It'll tell you where you are, but not a right lot more than that.