I have a Shipping Method for Free Shipping if price is >= $100. "show method if not applicable" is set to no..
I have a shopping cart price rule coupon. 10% discount. Free Shipping is set to No.
When a customer makes a purchase over $100, enters the discount code, and begins the checkout...the option for Free Shipping is still there!
I think it doesn't let the transaction actually happen, but showing it as an option is confusing customers, and causing transactions to be "cancelled".
Are you saying this happens when the discount drops the price below $100? That would be abnormal.
The 'Free Shipping' option in Shopping Cart Price Rules does not work in reverse as far as I know. What I mean is, it will not override the admin configuration to allow free shipping by setting it to NO for that coupon. So if the order is still over $100 after the coupon is applied it will still allow the free shipping method.
Magento calculates free shipping based on subtotal, not grand total.
But you can do something like this:
app/code/core/Mage/Shipping/Model/Carrier/Freeshipping.php
change line 60:
|| ($request->getBaseSubtotalInclTax() >= $this->getConfigData('free_shipping_subtotal'))
to
|| ($request->getPackageValueWithDiscount() >= $this->getConfigData('free_shipping_subtotal')
