Right guys, I'll cut straight to the business.

Went in my local guitar shop on a whim, and found literally the best amp for my needs going.
I've been wanting a JCM800 or similar for a while, to nail tones like Four Year Strong etc, but a number of things have been holding me back, which I won't bore you with!

I have a pretty limited budget, and have been looking at older Laneys (specifically the AOR pro tube 50) and used Blackstar HT-20, to get close to that classic British tone, but what I found was a Marshall Jubilee 2554 (I think...) converted from the black 1x12 combo (the silver ones are apparently rarer and more sought after) to a head, and switchable between 25 and 50 watts.

Basically, it belongs to the guy who runs it, but he seemed very willing to listen to offers. I have literally no idea how much he would expect, seeing as its heavily customised and completely beaten up, but a rare vintage and an 80s Marshall nonetheless.

Any ideas?
What he wants is unimportant, how bad do you want it and what are you willing to pay?

Figure that out and offer him 70% of your top offer. If he snaps it up, you offered too much...

But you have the amp you want, and there's value in that.
“Ignorance more frequently begets confidence than does knowledge.”
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As said above: Whatever you do, never start at your top dollar.
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Basically what Arby911 said.
According to Ebay they tend to run around a bit over $2k unmodified. Modification like that lowers the value obviously as far as collectors are concerned so you can use that to your advantage in haggling.
I would personally offer him $750 with the expectation of paying up to around $1200 or so max(you might do more if you want it badly enough). Anyone who knows more about somewhat rarer Marshall amps can feel free to correct me on that if I'm way off as to the actual value.
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