Im looking at:
I usually get 10 movies a month, give or take..
Each movie returned is a free rental instore so 10+10 = 20 movies
PLUS
I still get 2 free game rentals instore each month.
All for $18
And before you say "online renting is supposed to avoid going to the video store", I make 4 visits a month to blockbuster now as it is for the video games (rent and return) so its not that bad of a deal.