Second hand units tend to go for almost as much as new ones (certainly on eBay they do), so you're better off getting one brand new that no-one's buggered about with.
May as well go direct, all the main retailers sell the units at the same price anyway. I was told by one of them it's because whenever someone sells the units at well below RRP they suddenly find getting hold of more units difficult. Possibly bollocks though, more likely to do with demand outstripping supply.
