I used to always buy the player guides for the games in the day of the N64. It wasn't really an issue when we were all playing old NESes back in the day since the games were simpler and the more complicated games (such as SMB3) had already been figured out along the line so some people knew of a tip or two. I had a friend who had a Nintendo Power guide to SMB3 so most of us would figure out warp whistles and things like that whenever he had us over (he was the only one who had a guide out of all of us). Sometimes we'd just swap tips--I remember a lunchtime conversation in fourth grade where all we talked about was how to get through SMB3. I wound up being the first one of the gang to beat it and one of my longtime friends just beat it for the first time at the ripe old age of 22 on the VC a few months ago! (He got the game when it first came out in 1990). In irony of all ironies, the guy with the guide never beat it, at least not before he went off to college (and I don't think he took his NES, which was a top-loader, with him).
When the N64 came along I was one of the earliest adopters in my school (April 1997). Since a lot of things in SM64 were a bit tricky to figure out I got the player's guide. Two other early adopters of the N64 did not. However, in this case, the guide really did make things easier. I remember watching one of my friends trying to get stars in Shifting Sand Land without a guide. He spent over an hour and wasn't successful with anything he tried (this was before I had the game so I couldn't help him, nor could the other guy we were playing with that day). I was able to beat SM64 within three months thanks to the guide and would typically get one with every other game that came out for the N64 and GameCube because the Nintendo ones were so well-written. I didn't get the guides for the Game Boy Advance Mario remakes, however, because the games were the ones I already knew a lot about from the olden days.
About midway through the GameCube era someone told me about GameFaqs, so I just started going there instead. Double Dash was the first game I bought without a player's guide. Given the prices of these guides these days I usually just use the free resource, which actually is better-written some of the time. Believe it or not, I've found out stuff I didn't know about SM64 from re-playing it with GameFaqs guides.
I've saved hundreds of dollars by not buying these guides, although I did splurge on a MarioKart Wii guide since the rest of my family likes to play the game and I wanted a reference for them to consult in the house. (My mom is still upset that I never got a Double Dash book).
(Quick note: My mom is a MarioKart addict. She used to play it my N64 when I was at school and when she got a job once considered buying a GBA for Super Circuit alone, which she wanted to play on her breaks).
