The Holy Grail!
You can buy them newly manufactured for about $6,000-$7,000 US each I believe (
http://www.aviapropeller.com/texan.htm).
Be very careful with used blades. If the blades get too thin they cannot be overhauled and must be scrapped. There are many run-out blades for sale. If you buy, make the purchase contingent upon overhaul or inspection of the blades by a reputable shop.
I don't know if there is a definition written down anywhere, but blades are commonly rated A, B and C. "A" blades are like new. "B" blades should still have a good margin for future overhaul. "C" blades cannot be overhauled any further.
Here is a complete prop advertised:
http://www.barnstormers.com/listing.php?mode=usersearch&user=bmay%40keewatinair.ca&PHPSESSID=88bd53a5ca5b5277af9d1847f60f1da3