Do the math. Heck, give me a few minutes, I'll do it.
4 DVDs @ 49 cents + 1.99 shipping each + processing (lets say $1 each) = 11.96
You have to buy 4 over 2 yrs, so why not pick up the $14.95 deal so 3 more to go = $14.95 + 1.99 sh + processing = $17.49
Then 3 more .. at least $19.99 apice + $1.99 sh + processing = $68.94
$98.39 at least ... for 8 dvds .. $12.30 each.
But you will probally get some damn auto ship, so thats alot of trouble to return them. These are conservative figures, could cost alot more.