Anyone getting into a miniature war game is, or at least should be, well aware of how expensive they are. Even the cheap ones can end up costing you a lot of money due to the boosters/expansions being so cheap because what you get is random. I mean, sure you only *need* enough X-Wing ships to form a 200 point squadron. Maybe two squadrons if you're supplying the opposing force too. But who's going to limit them self to just that? No, you'll buy more models then the minimum needed so you can run variable battle groups rather then the same static group. Or because you want to play larger games.
****, if the local scene hadn't dried up, I'd still be expanding my 40k army. I can already run a decent army for the point value we would typically run. But I still 'need' more fast attack and heavy support in my army. Maybe another scout squad too.