I think both iPhone and Android have usable apps to see if you like it before getting a better, more accurate GPS unit. Must be worth spending the £5 or £6 for the app first
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I use a gayPhone 5, which in open air, has a GPS accuracy of approx 5m. 3GS has an approx accuracy of about 20m. Obviously, as soon as you're under tree cover, phones lose accuracy fast.
My BB 9000 had an amazing accuracy on gps and was rated as good as the accuracy on geocaching gps devices, if not better than some of the cheaper models. Something BB got right on the phone

However, one thing to consider (accuracy is not that important, as you gain experience you will know what to look for.....) if someone has placed a cache with a not very accurate gps device, your super accurate expensive gps device could say your within 1 foot, but in reality your 10/20 feet away.
So if you have a smartphone, buy the app for geocaching, the BB one is about £6, as is the iphone one....ive found plenty of caches with my iphone4/BB

However as i said in previous post i subscribe to geocaching.com (bout 6 quid/quarter) and i believe the apps (certainly the BB one did) had limitations on what you could do if you didnt subscribe. For example i can just start the app on my phone, click get nearest caches and they download, go find a cache and then send a log of 'found it', without the need to mess about with gpx files or having to go onto geocaching.com to log the find

One other thing to note is some caches are set to 'premium members only' and unless you subscribe to GC.com you cannot view them.
So if you are just going to see if you like geocaching, spend £6 on an app, spend another £6 on subcribing to GC.com for 3 months (you can cancel anytime) and go for it

Enjoy
