I've just picked up a Samsung CLP300 for £49.97 at the Yeovil PC World. It was an open box (so probably ex-demo) but had unused toners etc. inside. The same printer elsewhere cost over £100.
Doesn't show up online so I reckon this is just a stock clearance at individual stores.
A quick search online before I bought it suggests that you can get toner refill for around £40 for the full set and that the cartridges have a killer chip which stops them working if you allow them to run to empty.