Netflix, Blu-ray disc rental, cost per disc break down
 
 9.99/1 = 9.99
14.99/2 = 7.495
19.99/3 = 6.663333
26.99/4 = 6.7475
33.99/5 = 6.798
39.99/6 = 6.665
45.99/7 = 6.57
52.99/8 = 6.62375
 
The best plan: 7 discs
The only plans that make sense: 1,2,3,7