Amazon.com has The Matrix Triple Feature (Blu-ray) on sale for $9.96. Shipping is free with Prime or if you spend $49 or more.
Note, in stock but may require an extra 1-2 days to process.
Editor's Notes & Price Research
The Matrix Reloaded
The Matrix Revolutions
ETA: alternatively, as huy1224 pointed out, you can get the Trilogy plus The Animatrix movie for $12 from Barnes and Noble. There is a separate thread for this here credit goes to longmanj9 **** The B&N deal is dead.