Out of all of the serial numbered cards, the best one to get just might be the one of one. Actually there is no "might be," it is. There's only one copy of it in existence.
Like this Alex Rodriguez (In Rod We Trust!) printing plate I got from Bob Walk The Plank a while back. The second ever printing plate to enter my collection via BWTP.
You can see which of the four plates this one is, and which product it's from up there. You can also read BWTP's post about his experience pulling the thing here.
With eBay being the go-to place for baseball cards that people want and don't want, you can find a lot of actual 1/1's. That said, trying to compete with the entire internet for one card that you all know there is only one of is not fun and is why a lot of collectors don't bother with 1/1's at all.
But if you're like me and have a network of awesome people who know what you want, you can luck into some great cards.
So big thanks to Bob Walk The Plank, and as always thank you (the readers) for stopping by.
Take care :).