Autozone has $3 off most k&n oil filters with free ground shipping no minimum till tomorrow. Price reflected in cart.
This is about $1 or more cheaper than amazon add on
There are plenty of models available, insert your car make and model to pull up exact fit.
http://www.autozone.co
$3.69 examples below
PS-1010
http://www.autozone.co
PS-3001
http://www.autozone.co
PS-1017
http://www.autozone.co
PS-2004
http://www.autozone.co