A "grail gun" for me is something, typically an older firearm, that fills a niche in my collection. Certain models of old Colt and S&W revolvers, certain old lever-action rifles, certain 1911s or military rifles or handguns. Every now and then a certain modern production item pops up that I didn't realize until I saw it that it was a "grail gun." Example, a Winchester (by Miroku) 1873:
50 bucks isn't a deal-breaker for me. I will typically jump on it right there and then; too many times have I seen one of my "grail guns" and left, conscience telling me to sleep on, and have returned the next day to find the item sold right after I left the shop.
I keep a copy of SCS&W, and Fjestad's BB of Gun Values (and the mini-Blue Books for Colt and S&W) in my truck...And, just like the youngsters, I have this thing call a smartphone with the internet.
One of my main LGSs has layaway. 10% down and I got six months... Layaway is awesome. Not just for Christmas shopping.
But if it's something I just gotta have and shoot today, er, wait, new laws, I gotta wait ten days now to shoot it; there are options. Say, Cabela's Gun Vault or Bass Pro or Sportsman's Warehouse... they've all got ATMs inside. If a store doesn't, I know where the closest one is. Plus (and pay attention all you Millenials and G-Zers), I have this item with me called a "check-book." Now, if it's truly a Grail Gun that is more than, say, $2500, I might break out a credit card.
Kids are through college, cars are all paid off, credit cards are all paid off, we are set for retirement and the wife still works. Life is good.