As GeeTee says - you can spend whatever you like. I've seen PBX prototype autorockers go for $1500 and DC2's go for $1100, and that's before you've added shippng from the US.
You could get a nice Karnivor for £250 or a JOLE for about the same. And that's before you've started thinking about ups like MQ valves and tadao boards.
Sadly most of the stuff you see on here described as "mint", isn't and requires repairs. Which is easy enough if you know what you are doing, but a nightmare if you don't.
The great thing about them is you're unlikely to lose money. You can always sell it on later and prices are pretty steady, unlike the current stuff that loses 30% a year.