I don't know how long the sale will be, so order soon!
The Complete Blu-Ray series (I-VI) is just $89.99.
The pre-orders Blu-Ray sets for EP IV-VI and I-III are also on sale for $45 each.
Star Wars: The Original Trilogy (Episodes IV - VI) [Blu-ray]
Star Wars: The Prequel Trilogy (Episodes I - III) [Blu-ray]
If you still prefer DVDs, those are on sale right now as well.