Well it really depends on what u r going to do to it- exterior only. Interior? Engine? Suspension?
If u do the work yourself, u will save a fortune.
Parts r easily available but u can easily spend over $5 grand in parts on fenders, cab corners, paint, rockers, complete interior, etc. I dont want to tell u how much $$$$ I spent on restoring my dad's original 1984 GMC Sierra 3500 but it was ALOT. It's really a hobby and passion so if money is a problem then dont restore it because once u start it's difficult to stop & minor parts/issues always come up.
U need to show more pics of interior/body/engine. But figure if u r going to have body shop weld and paint and purchase all body parts- cab corners, rockers, floor, dashboard, seat, door panels, weatherstrip, trim, engine parts, etc. Plan a minimum of $10 grand and up. U always forget something and u have to pay for shipping/freight. It's a labor of love!!!