The 4-movie Lethal Weapon Blu-ray boxset is currently on sale at Fry's Electronics for $29.99 until January 10. This price beats Amazon's historic low by around $5.
You can order it online, with free shipping. Link:http://www.frys.com/product/7289513
Alternately, you can pick it up at any Fry's location that has it in stock. You can check in-store availability at your nearest Fry's location at the page linked above, using the "Store Pickup" option.
Here's a review of this product from Blu-ray(dot)com:http://www.blu-ray.com/movies/Lethal-Weapon-Collection-Blu-ray/38509/#Review