I had the Nintendo Power Guide, too, but I liked not reading it for tips of that sort. It was more of a narrative, almost like a pictorial novel of the game in some senses, which I really enjoyed. I still maintain my subscription to Nintendo Power (I had about a 5 year lapse there, but otherwise have had that subscription since 1989 or 1990; issue 20-something, anyhow), but it's not nearly the same these days. In some ways it's better, but I miss all the strategy components, and the cheat code corner, etc. It just felt like games were more full of secret stuff back then.
But the grinding was crazy. I didn't buy potions one at a time -- I'd instead grind levels up in that north forest area where you could fight ponies and ogres (whatever they were called there). Then once I was sufficiently over-leveled, I didn't need the 99 potions. I'd also try to get the level 3 or 4 spells before going in there, which took a ton of GP, but made taking out the wizards easier once you got to them.