That's impossible to know without knowing the true condition of the vehicle and to what extent you want to restore it. It's currently a non-running vehicle, this could mean that you need to replace a few minor parts - or it could be a blown engine.
You take a risk in buying a non-running truck - if it was an easy fix, then why wasn't it just fixed? I think Retiredwarhorses has posted here before that when he gets a non-runner, he just assumes the engine needs to be replaced. Sometimes he gets lucky, but not always. At a minimum, you're going to want to replace all fluids and hoses, you need batteries, a fuel tank, headlights, mirrors/brackets, glow plugs, ground harness, you'll probably want doors, seat cushions, etc. That's gonna be a several grand easily in parts. To replace everything that should be replaced to make it truly 100% without seeing anything else that needs to be replaced, plus a paint job - the costs escalate quickly.
I firmly believe that unless you're a tinkerer with patience, ready access to parts/or a cash reserve equal to what you pay for a non-runner - you're better off spending more up front and getting a running truck. These can be money pits as it is and that pit just gets deeper if you have to start tearing off heads or worse, replacing the engine.
I do have a couple sets of X-doors if ya want to get a head-start.