For new clothing:
http://www.alvarezenterprises.com/ (quality charra and western outfits)
http://www.samswest.com/
http://www.cowboys.com/westernwear.htm (links to many other sites)
http://www.country-western.co.uk/ (for those in the UK - includes line dancing
outfits!)
Or do a search on "western wear" (in quotes) using your favorite web searcher.
For vintage clothing go to http://www.rummaging.com/resale/shops.html and click on
your state or country.
I'd agree with what Junior said - most of this stuff is hard to find at any price.
