Tha depends on the scope. I mean if I'm shopping used I want to get as close to 50% of retail as possible. But the top of the line I can reasonably spend on a scope is 1500 - and that number would mean Im stretching my fun budget.
I'd like to get at least down to 475 - 500 on a 599 scope (including the sh10 code, this place rocks)
If it's a 3k scope like a theos I'd like to be at 1500 to make the move worth it.
Personally I'm not a good enough shooter yet, and I don't shoot long enough to take advantage of a scope like that though. For me, my best bet (i think) is to find a used dnt or another used Cronus gen 2 and a good mount - like
@FuhQ suggested - and spend more on ammo.
But for the right deal ... I have another 2 weeks realistically before the rifle arrives at my FFL and it clears the delay that I always get personally.
So I have some time and I'm interested in knowledge and opinions!