1975 Fuel Injection VW Bus SPECS:
HOW MUCH CAN I SELL IT FOR?
Here's some stuff to think about:

BODY: dent on front right fender, black primer for rust prevention on back grills (behind windows) and driver door frame, beginnings of rust around window frames (not all), rubber stripping around windshield needs to be replaced.

INTERIOR: custom seats with headrests, panel missing on driver door/sliding side door, no middle seat, green tiger stripe curtains, gas gauge not working, heat grills on dash deteriorated, glove box needs new door.

TIRES: in great shape/UniRoyal All-Season Laredo

ENGINE: I don't know how to describe specs (you probably know...) but in great shape except it has been sitting for awhile (2 years).  The "running rich" or fuel injection problem is the only thing wrong.  I have had a few different mechanics try various things: heat sensor, replacing fuel lines, etc. 

The symptoms: I'll be cruising along and suddenly engine will stall as if flooded.  Bus sits for half hour to an hour acting like its flooded then I am able to turn it over and drive again (until the next time, not frequent))

WHAT ELSE?: Had major work done by Larry's VW Service (the best in the Mid-West!) while driving through in '07 on I-40 too fast.  He basically rebuilt head, replaced 4 pistons and rings, front air cooler, engine mounts, other seals, hoses, CV boots, rings, etc.  Costly but beautifully done....got the receipts for this/ AND all other work since I've owned it and from prior owner.

247,813 miles
Thanks,

It's hard to give an exact answer other than it's worth whatever someone will pay for it.

Geography plays a big part, the market for buses in one area would be completely different than another. You didn't mention where you are from, but I assume not here. Finding a rust-free anything in this part of the country is immediately going to make it more valuable. Out on the west coast, it's not as much of an issue.

Pictures would definitely help, but generally a few grand isn't bad for a running driving bus. Fuel injection problems can be really simple for someone who has experience with Bosch FI, but in the wrong hands all those parts might be removed and replaced with a carb.

Receipts showing service and repair are definitely a plus, it would make anyone more comfortable knowing it had been cared for properly.

Your best bet would be to do a search on thesamba.com for ads of comparable buses in your area. That will at least give you a starting idea of asking price and you could go from there.