Lego's last patent expired in 1989, and their legal battles with the clones began. Then came Lepin, which went further with "Indiana Adventure" or "Star Plan" replica sets. Lego's legal hopes in China are dim. So have a look at the discontinued $50 Flying Wing set selling for $25. The discounts really start to matter when Lego is asking ten times that.
Personally I'm happy bringing home new Lego floor sweepings, or used loose pieces by the pound.