Among the cheapest 'new' scopes you'll find is the Rigol DS1052E, which is LCD based, quite small and can be as cheap as $299 if you can find a sale. I haven't personally used one, but on the surface they look quite reasonable for hobbyist or semi-professional work.
My experience with used scopes so far is 0-for-1, with batter #2 at the plate. I got a free (as in beer) Kenwood 100MHz surplus inventory scope from work, which was great for around 4 hours or so until it completely warmed up and a latent HV issue showed up (random KABLAMO! arcing and ozone generation, likely somewhere in the flyback transformer.) I recently tried my luck again and got a 2-channel Fluke Combiscope, which I know works for at least six hours without risk of fire.
As others have said, it's buyer beware when getting used gear from auction sites. Many scopes, even older models, are still serviced by their manufacturers, but the price per incident will likely be much higher than what you paid for it. A new scope will at least have a 1 year manufacturer's warranty in case something goes horribly wrong. That being said, good quality scopes that haven't been abused can easily last decades.