W3 Custom Product Options

Shopify defaults to 3 levels of product options, and lets you create variants along those 3 planes. I needed to offer customization on 4 levels, and CPO has been OUTSTANDING in that capacity. It's so versatile, that I even offered a 5th aspect of customization that has an upcharge. Not only is the app versatile, it includes extensive easy-to-implement instructions. And the one time I hit a snag using snippets, their support team quickly helped me out with easy communication and intuitive understanding of a shop-owners needs. Worth every penny!