First off, Mike, great post - you got 2 first time posters on this thread so far! Awesome!
Holy Grail - as a youth. Hmmm. I don't remember buying a lot of individual cards. At one point (early to mid-1980s), I was trying to get all the base set cards of all the players I collected (the "superstars" of the day). I collected all the usual suspects, Yount, Brett, Ryan, Rose, Reggie, Winfield, Sutter, and several others from the 1970s, and of course the "new guys" like Sandberg, Ripken, Boggs, & Gwynn. Working for The Baseball Card Shop (Westville, NJ) at the time, I had access to almost anything. Plus there were shows all over the place, and cards could be had for cheap at those. So I organized, the best I could, and with the help of my SCDs and other sources, I figured out what I was missing for each player. Most of it was dime and quarter type stuff.
The only card I bought, as a youth, that was at a price I did a double-take on was the 1974 Topps Dave Winfield. (Remember, this is when cards were 3 cents each for commons and most stars were rarely over $1.) I think the shop owner wanted $8 for it. It booked at like $25 at the time (he was always very generous to me). I gasped, but bought it. Still glad I did.
I wouldn't consider that to be a holy grail type card though, it was simply one of hundreds on my want list. But it was a card *I* purchased.
The two cards I really wanted were the 74 Schmidt and even moreso, the 73 Schmidt/Hilton/Cey. I was around 22 when I traded to get the 74 and my wife's uncle gifted me a 73 about 10-15 years ago (the same one I bought my 72-77 Topps sets from about 3 or 4 years back). So, even those I didn't "buy" (the stuff I traded away to get the 74 had been a gift as well).
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).