Yeah FFII is very coy about how all of it's mechanics work. Another hallmark of Kawazu's design philosophy for anyone who has ventured into his other series.

For money woes, the big thing to know in the early game is that you have to kill all the enemies, you get a penalty if any run away. The best way to get money is by selling items that they drop, especially magic scrolls. One of the best early game power leveling tips is to get your barehanded strong enough with your team to be able to pick fights with the imperial captains in Fynn. In addition to having one of the highest enemy levels for a good chunk of the game, they drop Flame Bows and Toad and Curse Scrolls and even Gold Armor. Most of those items will make farming them easier, and you can sell them for a small fortune. Once you get the canoe, you can then try to get to Mysidia early in order to purchase the Swap spell for the rest of your team.

Don't worry about getting high level magic though. Technically after a certain level, their effectiveness increase is marginal at best. So getting magic up to level 8 or 9 is probably for the best unless you're hoping to see all the cool new animations in the remake. You'll want the basic three elemental spells and Flare to be decently leveled, but you should focus on healing, life, and buff spells the most.