It may come as a shock to most readers, but I don't remember what my first pack of cards was like. The first purchased CARD, sure (1951 Bowman Dale Mitchell), but the first pack?
Best as I can recall, it would have been around the summer of 1978 or so. The reason I say that is because I distinctly recall opening a pack and referring to them as "the written kind," since the team names were all in cursive. But, that could be a false memory. Or maybe I just didn't collect that many of those.
The cards I remember opening were later, in about 1980 and '81. We had Topps and Fleer, and some new card company with really bad pictures but slick cards called "Donruss."
I was in 3rd and 4th grade when I really started collecting, really started paying attention to WHOM I was collecting. Back then, it was Indians, of course, but also Pirates and Reds and Astros. Omar Moreno, Willie Stargell, Carlton Fisk, JR Richard, Rickey Henderson, and countless others. Soon, Fernando Valenzuela was THE card to have.
I was a "dumb" collector as a kid. I actually GLUED my cards into spiral notebooks in order to collect them. It never occurred to me to put them in a shoebox, and I don't even think I knew what 9-page pocket pages were, or if they even existed. The cards that i was willing to trade were bound with rubber bands (gum bands we called them), usually by team, though sometimes by player.
There was a dairy store (like a mini five-and-dime) that was about a half-mile from the house, though it seemed much further than that on bike. I would go with 5, 6, sometimes 10 other friends to the Dairy and we'd plunk down our money to buy packs of cards, liquid-filled wax bottles, and Swedish Fish. We'd all gather in the parking lot, hurriedly opening our new treasures, eager to trade away the 'junk' we didn't want.
Many of the cards got dumped in the trash can or were taped to our bike spokes (yes, we really did that). The rest of the cards were mainly used for flipping. Now, we didn't know flipping from Adam, so we made up our own flipping game, and to this day I have no idea if we were doing it 'right' or not. Each person would toss about 6 cards onto the floor. Then, we would take turns flipping the cards we had in our hands. We held the cards by the long edge between our index finger and thumb. Then, we would flick our wrist and send the card tumbling over and over until it reached the ground. As I said, each person would take a turn. When the card landed, it remained on the floor unless it landed upright (face-up) on another card (or pile of cards if they were all face-down). Each person flipped one card at a time, trying to get their card to land face-up on a good pile. If you were really good (or lucky, usually), your card would land face up across TWO piles! That was pretty rare.
We also played a game where you would toss cards into a ball cap. Or try to, anyway. The cap was always far enough away that actually landing a card in the cap was something next to impossible. But, if you DID land the cap, you got ALL the cards on the floor!
I kept collecting pretty steady during those days, well years, of my life until we moved. Then we moved again. By this time, I was in 5th and 6th grade and the kids in my new neighborhood weren't much on collecting baseball cards. I still bought some, off and on.
But, looking back, my habit did not start with a particular pack of cards. It started as a bunch of kids buying cards to play with. We collected cards based on teams we liked, players we admired. We had never heard of "book value" and I don't think we would have cared if we had heard of it. We concocted trades based on the cards we knew our friends wanted ("I'll trade you Yaz for 10 Indians...").
Looking back, we collected because it was fun. And even now, some 30+ years later, I get the same excited feeling when I open a pack of cards and find a player I collect, or an Indians card - even when I already have it....