Giving free product for signup. Product is 1.37 and I am giving Free Shipping (through the Shipping Module NOT via the discount coupon as I am aware you can't offer a percent off AND free shipping).

See below. Says I owe the customer .01 ... I am in Ohio and my tax is set correctly to 7.5%

Help!

$1.37 $1.37
Sub-Total:


$0.00
Free Shipping Options (Free Shipping):


-$1.37
Discount Coupon: welcome777 :


Total = $-0.01