Super Marios Bros 3 and purchasing video games in my household.
My son asked me when Super Mario Bros. 3 came out, and I had to Bing it. The answer is October 23, 1988. And I was suddenly struck with the weirdness that I have specific memories of the release of Mario 3, and yet I was only five years old. That shows you how important it was to my five year old brain. The big thing I remember is it being a big deal for two reasons...
1) it was Mario and everybody loved Mario, plus it wasn't Mario 2, which was just weird.
2) it was really expensive for a video game at the time, and if you're parents weren't just basking in money sun waves or willing to lay down that kind of cash for a video game, you probably didn't get it. We didn't get it.
But our parents had a pretty strict rule about video games, we had to buy our own games. They never bought us games. Not even for birthdays. So we had to save up our own money to get new games, or consoles for that matter. I don't think our parents ever bought a video game related product. Looking back, it's quite impressive on their part and we never felt ripped off. They just made it clear that it was up to us to save our own money, if we wanted to purchase video games.