ZC1.39h

I'm perplexed (what else is new?).

I've been racking my brain trying to figure this out on my own but am coming up short.

I'd like to offer a "Buy 4, Get Free Shipping" Sale/Special but can't figure out how to apply the free shipping to specific items.

Basically if a customer buys 4 items from a specific category or sub category I'd like to offer them free shipping for those 4 items only and not for everything in their cart.

I'm sure that I could mess around with coupons and make it work but I'd really like to get it to work without asking the customer to enter a code to take advantage of the sale/special.

Is this even possible using ZC?