Amazon has Police Academy DVD Collections 1-4 and 5-7 for $9.99 each + FS
With Prime
Police Academy 1-4 ($9.99) contains:: http://www.amazon.com/Police-Academy-1-4-Collection-Favorites/d
Police Academy
Police Academy 2: The First Assignment
Police Academy 3: Back In Training
Police Academy 4: Citizens on Patrol
Police Academy 5-7 ($9.99) contains:: http://www.amazon.com/Film-Favorites-Collection-Assignment-Nati
Police Academy 5: Assignment Miami Beach
Police Academy 6: City Under Siege
Police Academy 7: Mission to Moscow
National Lampoon's Loaded Weapon 1:
Alternatively, you can buy the whole Police Academy collection on Amazon
Instant Video: http://www.amazon.com/Police-Academy-Collection-Steve-Guttenber
for $9.99
Cheapest for the entire Boxset is $59.99 at Bestbuy: http://www.bestbuy.com/site/Police Academy Collection [7 Pack] - DVD/6311939.p?skuId=6311939&ci_src=14110944&ci_sku=6311939&ref=06&cmp=RMX&loc=01&id=1347130
(Shipping and Tax YMMV)