Offer him £20 and tell him how handsome he is Seriously the welder would have been around £600 new and if it still looks good and you know you can go back to him if you have problems £250 to £350 would be fair.
I circumstances like this I would tend to put myself in his shoes, knowing how much I had paid, the use it has had and what I would be happy to accept wihout feeling I had been robbed.
Also depends on his financial situation, nothing worse than someone who is happy to leave stuff doing nothing and does not need the money..
In excellent little used condition about £350 to £400
In good condition with fair use £300 to £350
A bit workshop dirty but working good £250 to £300
All based on a new value of £600
I would keep fighting for him to name his price though..he will have one in mind.
Well 1 bottle of 10 yo Macallan 3/4 of a bottle of Bells, £80, plus a taxi ride home and i'm the new owner of the Murex. so about £110 all in.
Just need a lift back to collect he car and unit when I recover from the inevitable hangover tommoz,
It also came with a Esab auto mask, and a 4ft high bottle of 5% argon, bottle is yellow and i'm told it was a refillable but never needed filling, and a double gauge head, one gauge shows the bottle pressure and one gauge shows the flow pressure. It still has the original roll of wire, it's a bit crusty looking but he had the sense to roll it back out of the torch and folded it through a hole in the spool
Over all I'm really pleased I would have gone to £200, only thing is it has a huge blue round plug, can I run this thing off 240v through a 3 pin???