When I was a young pup and Mechwarrior was a big hit, I certainly didn't have as much discretionary income as I would have liked. I loved that game, but it was pretty expensive for me.
I didn't get an allowance; I did chores around the house for money. I would get maybe $10 for mowing the front and back lawns, $10 for sweeping the floor in the living room . . . I also had a sister, who often liked to underbid me for jobs and get them done before I did. Needless to say, I didn't get much money to play with.
But I still decided I was dedicated enough to the game to buy the miniatures. I would also play with my friends' minis and trade the factions I didn't want for the ones I did (Dragon's Fury ftw, btw). If I had wanted to, I could have photocopied the clix dials and made cardboard versions, and then built up the little paper models that occupy a sizeable chunk of my hard drive for proxies. But I didn't want to. Firstly, I felt it made me look too cheap to buy the miniatures, but I also didn't think the proxies looked as good as the real thing and wouldn't have been as valuable to me. So I typically bought the minis whenever I went to the book store with whatever money I had to spend on them. I managed to build up a pretty sizable army over time, even with getting maybe $5-10/week on average.
I'm not saying you should dedicate your life and income to X-wing. I'm saying that while I was more than able to afford a collectible miniatures game, it was within my means. If X-wing is not within your means, then don't buy it. Build those awesome little paper miniatures from Momir Farooq's website, or maybe use Galoob Micro Machines (you can get many of them on eBay for next to nothing) or even 2D cardstock cutouts. Judge what this game means to you, and spend however much - or little - you want to on the game.
In short, do what you can. It's all you can do.
And if you ever play me, don't be afraid to ask to borrow my minis if you don't want to proxy.