I don't conflate 'price' with 'value'.
The term 'value' is meaningless to me, unless it's taken in the context of what I'd actually do with an amp, instrument or other studio tool.
No matter how great it sounds, and no matter the price - whether high or low - an music making device is not a good value if it sits unused in a corner.
One that gets used for the reasons one bought it? Another story.
Example: I've got an $800 mic stand that was a good value, given the projects I've used it on, and the need for a tool that will hold a heavy mic and keep it firmly in place for an important session.
Most people wouldn't think it was a good value, and for them I might agree. Context is everything.
An amp that has been a consistent first-call tool, and even better, one I make good money with, is a great value. Doesn't matter what the price was. Amps like these pay their own way.
So I'd say if you're going to use an amp and derive $, or long-term pleasure, or both when using it, you got considerable value.
Doesn't matter what it cost. If the results of owning it are on the good side of your own, individually considered, ledger, it represents good value.
If you're not using it, I don't care how good it is for someone else, it's money down the tubes.