+1. If you have a decent tailor, you end up with something of amazing quality that fits you perfectly for a tenth of what you'd pay for it new - even if you'd never actually pay for that new. About 50% of the stuff I keep for myself goes to the tailor eventually. That said, a perfectly fitting but beat-to-hell shirt is still going to look like a beat-to-hell shirt. I've definitely made mistakes on getting unworthy stuff tailored.
I don't usually tailor shirts but I just took the plunge and tailored a single-vented Gianni Campagna 3-roll-2 navy blazer with ticket pocket and gold buttons. Had the sides taken in and the sleeves slimmed for $100. So, tailoring costs plus acquisition cost of $12.99 got me a $5k SC for $112.99. Still a pretty good deal. Next up is a cashmere Fernando Caraceni gun-club check SC.