Well good for you. That doesn't mean that there's something wrong with people who want to spend more on designers because they think it looks better. People can dress the way they want, if a CK shirt tie and pants is good enough for you, fine, CK doesn't look bad. I have a couple of Ck shirts. It doesn't cost under 30 bucks though, I don't know where you got that, Ck ties msrp 55.00, shirts from 45-85ish, pants and jeans 100-120.
But don't hate just because people like the way certain designer clothes look. My Dolce&Gabanna shirts look way better than anything Ck I own, and I think the way they look is worth it. So let people spend their money how they like.
That being said I think there is a line to be drawn on the low end... seriously, I know it sounds kind of stuck up but I don't really want to hang out with people who look like complete slobs. Now most of my friends don't spend stupid amounts of money on clothes, but they still buy what fits their style and try to look good. If your foremost concern in buying an article of clothing is that it cost less than 30 dollars, well, you probably look as cheap and shoddy as what you're wearing.