I have a name for you, and they have stores all over the US. Two brands, actually, where I've found innumerable $300 lambswool sweaters that fit perfectly, $900 Calvin Klein cashmere wool overcoats, and Donald Trump and Ermenegildo Zegna ties.
It's called the Salvation Army. Nothing I buy there has ever cost me more than $8 or $10, except for a Gap leather jacket that also fit perfectly which I paid $25 for. The ties - like $70 or $100 ties - all came at $0.99 each, the overcoat was $6, and the sweaters have never cost more than $3 apiece. An Armani dress shirt was like $2 I think. I did splurge once and buy a tie for $1.29, but that's rare.
You may have to hunt for a bit and return to hunt some more, but you can find truly unique stuff really cheap, and often high end brands if you're brand-conscious (which I, admittedly, am). People have commented to my family, making asides that I must make A LOT of money at my job to dress so well. Couldn't be farther from the truth!
Also try Goodwill.
Yes, the Salvation Army has turned me into a clothing snob. The only thing I don't buy brand new are shoes, socks, and underwear... which comes from JCPenney, Gap discount rack, or A&F (they have really comfy trunk briefs if you wear them)