I would love a coupon that allows me to specify a free product if the sale is over X amount. The link would have to be based on ProductID or SKU if possible. I certainly wouldn't want to lose realtime inventory tracking.
An option for whether shipping is applicable on that free product or not would be useful to some.
A customer meeting the coupon amount would apply the code and the product would appear in the cart at a price of $0. If they remove items from the cart, the free product would disappear if the cart total drops below the coupon threshold.
This would be a great addition to the X-Cart arsenal! The most important thing is to treat your customers well, have the email templates explain what you need them to, and the opportunity to market/sell/promote be everywhere.
