Nintendo Power wasn't specific to the 90's, or even the 80's. Its final issue was released December 11, 2012, so it would be inaccurate of me to say that it was solely a memory for anyone who grew up in the 90's, but let me also say this; it was far more important in the 90’s. The reason is simple. In the early 90's, we didn't have internet. In the mid-90's, your school would have internet and the occasional friend might have internet, but it was an extremely rare occurrence to "surf the web". In the late 90's, almost everyone had internet, but it was still dial-up, pay by the minute internet. And most of all, the internet just wasn't that great yet. Most of your time in the late 90's online would be chat room related or downloading whatever you could find on Napster, and then waiting 30 minutes for the wrong version of the song you wanted. The point of all this, is that you couldn't go online to find the answer to absolutely everything. And, "everything" in your childhood years, was video games.
Cheat codes were acquired one of four ways. 1) Word of mouth. Before social media, your best source of information was the school playground. If a friend knew a video game secret, you would hand over all the pudding cups you owned in exchange. 2) Stumbling upon it by accident. Anyone who's anyone button mashed during the opening credits of a video game hoping they might stumble upon a way to warp straight to the final boss. 3) You called the Nintendo Powerline. This option was only reserved for the super rich kids or the ones who would call without their parents permission and then get beaten with a slipper. 4) Nintendo Power. The best bang for your buck, and the assurance of not being fed shoddy information from the kid who was destined to be a pathological liar.
Aside from Fun Dips, a pack of candy where you would dip candy into more candy, your allowance money was best spent on a Nintendo Power magazine. Nothing else had the lasting payoff that this magazine had. The first issue debuted in July/August of 1988 spotlighting Super Mario Brothers 2. The primary focus of the magazine was to provide tips, tricks, strategy, reviews, and previews of upcoming games. It was everything you wanted in a video game magazine.