Once again I encountered a Magento query in my freelancing career and here is the solution.
Recently a client also wanted to sell "Gift Certificates" as a product with no shipping rate since its a virtual gift card.
I search around a lot but didn't got solution any solution, also found that so many people asking the same question on Magento forum with no answer except only solution was to purchase an extension ranging from price 80$-360$ to handle shipping rates. Hence I suggested my client to purchase the extension.
But that wasn't convincing solution to me because if an extension can do it then there must be a solution. After few days, I found that new Magento version has a feature called "Shopping Cart Rules".
It provide multiple ways to handle shipping rate, in short, you can create any sort of rule of your own to handle shipping rates.
Let’s run through a scenario to get a better understanding of how to configure Magento for free shipping on specific category/products.
1) In this scenario we will be offering free shipping to Products in Category "Gift Certificates" having category Id : 10
2) Set up through Promotions -> Shopping Cart Price Rules -> Actions so that the free shipping will automatically apply if the conditions are met.
3) Since our Shopping Cart Rule is not limited to any product attributes, we can either choose “For matching items only” or “For shipment with matching items” in the Shopping Cart Price Rule Actions as Free Shipping option.
4) Now here, if we select “For matching items only”, if there are multiple items in the shopping cart, the free shipping will only apply for the product within the "Gift Certificates" category and other shipment charges on non-"Gift Certificates" items will be calculated separately.
This is just of many techniques to offer free shipping to your customers.
P.S. I would suggest to purchase Extension if you have more complex shipping requirements.