Boxify

It took me less than 15 minutes to get Boxify up and running. We ship primarily one product, but have some seasonal items as well -- meaning we have multiple box sizes, and both boxes have their own weights, which is where we ran into trouble with Shopify's default settings. We also wanted to use our negotiated rates and were very disappointed that on the Advanced plan we couldn't set multiple box sizes! But Boxify solves all of that -- and you can be on the Lite plan to get negotiated rates, which is a nice surprise. This app is perfect if you need multiple box sizes and/or negotiated rates. Couldn't recommend it more, top-notch support too!