For 2nd user machines try north west keys, 0151 9441187
www.nwkeys.co.uk
they stock recon and new machines of all kinds.
i know a guy selling a number of 2nd user smarty 2 cylinder cutting machines at £300 all in, fully reconditioned with new cutting wheel etc, as good as new.
It depends what you are after. a good light use machine is the tempest from sks, but a pain to use and keep changing wheels, a good dual machine is the SKS cyclone.
are you opening a shop or a market selling keys ? as if not and going mobile, then you will find little use for the machines, as you will cut very few. a good add on later on, but money is better spent in other places when setting up.