Is it possible to get an original DEC pdp-7, if so how much would it be? I've looked around the internet, but I'm not finding anything.
In short: no.
A well-researched list of PDP-7s sold and their fates is available here from soemtron.org. There were approximately 50 PDP-7s manufactured, of which only
4 5 are still known to exist. They're all in museums.