You must be a nubie to the Z market. Dash covers come in two types: (1) carpet style that you can buy at Pep Boys or other outlets, are essentially a piece of formed carpet that lays on top of the existing dash by way of Velcro, or (2) a vacu-formed piece of plastic known as a dash cap. It is textured to look like the original and covers most of the original dash, including gage pods. These cost $70-90 depending on supplier. Motorsports in CA. has some nice ones. They adhere with glues or foam tape and look better than the carpet and certainly better than the cracked original.
really the best way to go is check a junkyard if you have one 280ZX's are the most common of the Z's at junkyards i think at least around here. So basically if you can just grab one off of there you should be able to get it for cheap. vic brit and motorsport probably sell it for 150 and above so i'd say for a used one max of 75 dollars! don't forget though you should get new weather stripping, and when you take out the front windshield at the junkyard or whever to just cut up all the rubber and then push the window from inside real gently. i won't go into it here but someone told me that if you do it like the nissan manual describe using a screwdriver it will shatter
I was at the junkyard too... I saw mainly 280 Z's... went in looking for a nice 3.70 rear end and came out with a windshield...... I saw an old Z with a dash cap on it and lost my pliers.... should have called it a day there... because when I was in Sears looking at the craftman tools....I ran into an old girlfriend....