As a collector on a budget, many of my books from this era are lower grade. These aren't my best five, but they've got to be among my favorites for various reasons. These are more Atomic Age, and all probably qualify for October's cheap faves thread, but as somebody said, whatever.
Young Love #2, my first GA Kirby book, bought for a few bucks on ebay 20-odd years ago, give or take.
I have an LCS near my job, which is my favorite and one in the town where I live. The owner of my favorite one is always turning interesting stuff up, my local one not so much. So when walked down the street and saw Cap #78 on the wall I scooped it up immediately. They also had an Astonishing #30 for $125 that night but it had CT; I regret not taking that one at the same time despite the CT.
The condition of this Yellow Claw #4 is nothing to write home about and I find the cover kind of meh, but the Kirby/Severin interior blows me away. I love this series and this is my favorite issue.
I picked up almost a short box full of PCH and pre-hero Marvels years ago and set about selling my dupes and issues I could live without to amortize my expenditure. This one didn't sell. I was glad then and even more glad now.
Here's a reasonably nice one from that same box, but this one was a keeper as soon as it was in my hands.