FFT:WotL is pretty cheap if you find it. I figure any Gamestop near you would have it but I highly doubt Amazon will have it for more than $20.

The job class system applies to everyone, story characters and the generics, though most story characters get unique classes. There is no reincarnation system just FFV's job class system with the extras Velo mentioned. The job classes also determine what stats are raised as you level up, so keeping a character in Mage based classes will keep their physical ability low but raise their MP dramatically. You're equipment also plays a large role as many of them give HP/MP bonuses and other stat modifiers and buffs, if you have played FFXII, you have an idea of what to expect with equipment.