Target checkout/add to cart button based no item vs. the entire page.

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Removing conflicting form ID

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Changing 0.1 to 0.01 allows for values of 0.90 and 0.99, etc., #166 and additional number formatting fixes done.

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>