I'm sure I read somewhere that Garmin were doing some deal recently where they were selling reconditioned ones. Might be worth contacting them.
I had a 305 and the tones on mine became nearly inaudible but I'd had it less than a year so I returned it to PC World and got a refund because they couldn't get me another one. I was quite happy with this because I'd won a 405 in the meantime.