Should I get final fantasy 1 or 2? I've never played either of them but I'm willing to get one for $4.
Final Fantasy II is my favorite Final Fantasy -- it's easily the most experimental the series has ever gotten (conversations with NPCs based on keywords, a novel leveling system (later imitated by the Elder Scrolls games), and the first appearance of a well-defined cast and plot in a jRPG). The remakes/rereleases have removed the jank (grinding, etc.) and really brought the game forward. It's definitely worth playing.
FF I is only notable for being the first FF. I'd pass on it.