I do care about my appearance, and try to dress snazzy without conforming to any trends. I feel like the clothes I wear can say a lot about the person I am, and I definitely agree with the sentiments that being well-put-together can make you feel more confident.
I do like my shirts, I generally head straight for the sales rack. The most I've ever paid for a shirt was $40, which was from a Radiohead concert and they're basically my favorite band ever so I was willing to part with the money... otherwise I cringe if they're over $20, but will occasionally fork over $30 for a particularly cool one.
As for pants, unless I want to wear a black shirt, I wear the same black pants every day. They're these pretty nice stretchy skinny jean things (cough from hot topic cough), I've literally gone through and replaced 5 pairs (and counting) just cause they're so stretchy and go with pretty much most of my wardrobe. They're $40. If I ever buy a different pair of jeans I never venture about $20 though.
I had a weird phase with buying interesting sneakers for a while last year, and though now I have quite an assortment of Vans I remember them being pretty pricey... but I rarely wear out shoes, it takes me yeeears. Even these black converse that I used as my workshoes for two jobs over the course of 3 years still have a long way to go before they're rendered un-wearable. Though they are finally showing some signs of age... fading, rubber is splitting a little where my foot bends. that's about it though. So I think even if they're expensive I feel like I make them worthwhile. $60 is my maaaxx on sneakers, though I might go higher for a good pair of boots...
...mmm, like my wonderful shin-high white shiney doc martens. those were a good investment.