I bought a Garmin Nuvi 370 with USA and European maps on Ebay new for just over £110.

I went for the Garmin Nuvi because it has a headphone socket and the battery life is about 8 hours before needing a re-charge. I can now use the sat-nav on my motorbike and also use it on foot. The nuvi is also good because motorways can be turned off and the unit can be used by learner motorcycle riders. BTW it's not waterproof so can only be used on dry days or needs to be put in a waterproof plastic bag when being used on a motorbike in bad weather.