I think it was $6.75 back in '76. Now, it is rarely at auction and it would go $150-200. The '74 Heitz Martha's Vineyard (more than 4,000 cases produced) hammers around $800 in California (retailed at $25-35 on release in '78 or '79). The VME was the better wine. Had them both at the same tasting 25 years ago. A '68 Heitz cab was on the same level as these other 2.
If you want a world class wine for cheap get a good Zinfandel for around $50. I don't know the best years as I've not collected wine in some years. Zin does not age well so you don' want to lay them down in the cellar. Drink them.