First Sabretooth for a buck. Damn, Rollo, way to one-up a dude.
I remember one thing I did in my comic-addict high school days. Ghost Rider #1 was in the first Previews I got. I didn't know he was an old character who folks thought was a joke. I just saw "holy shit a flaming motorcycle-riding skeleton screaming he's going to kill a dude fuck me this is awesome" and ordered it. As you no doubt recall, this series went through the roof. And that's when I found out there was a (shitty. admit it. shitty.) previous Ghost Rider and first volume. Those issues were now worth a shitload, especially his first appearance. I didn't buy the Deathlok mini when it came out (prestige-format miniseries were out of my budget, since I looked at cover price and not total spending on all comics, so I know I missed a ton of good stuff in favor of shit like Youngblood), but started getting it when the regular series came out. I also observed his early appearances were worth quite a bit.
So I kept an eye on the 70s heroes who were forgotten. I don't recall who showed back up first, but I think it was Cage in Punisher, and solicitations mentioned he was getting a new series. So, bam, I bought every Power Man and Iron Fist I could get my hands on, including the first appearance of the guy for just $5. And I discovered it was a pretty awesome comic. Then Namor resurrected Iron Fist, so I was looking doubly hard for his solo appearances, and got Marvel Premiere #15 for something like $7. A few 70s heroes were just so dumb I couldn't see them returning, but Machine Man looked promising. Though it never panned out as an investment, the Kirby issues of 2001 and Machine Man are worth searching eBay for, trust me. I started on ROM after Nova mentioned the Spaceknights in New Warriors, but soon learned he was licensed and wasn't making an effort to find them. Not that I wasn't looking; I wound up loving the series (I'l
KILL to get the whole thing in paperback... no, really, I would fucking murder Justin Bieber for that shit), but there were plenty in quarter bins to keep me occupied.
Speaking of which: the local mall used to have periodic antique/collectible shows. A few regulars had comics. They just didn't know what they were worth and apparently never thought about looking at price guides. Anything with "X-Men" on the cover was guaranteed to be selling for more than it was worth (aside from one guy who had #244, the first appearance of Jubilee, understandably high on my priority list, for $1 because it "wasn't John Byrne or Jim Lee," or the guy who had #248 for $1 because he didn't recognize Jim Lee's early style). So I always hit the quarter bins, where no one else looked, and came away with stacks and stacks. One time I had an older Green Lantern issue among the Power Man & Iron Fists, and read it first when I got home. Hal was sucked into his battery, or something, and, holy shit, another GL calling himself Guy Gardner shows up to find him, then winds up in a coma. Pulled out the price guide to verify, and, holy shit! It's not the first appearance of Guy ever, but the first appearance of him in a GL costume--worth more at the time than his actual first appearance as a civilian.
The dropping prices of back issues do not seem to have treated that one very well, though.