I suggest you understand your user's needs and behaviour first before you go with a card sorting approach. You need to take a user survey or interview to understand what kind of information they are looking for when they purchase the product. Every user has different needs, so you must first understand the overall picture before categorising which information they are looking for if they want to complete that need, and later on you will allow them to categorise their needs with a card sorting approach.
Imagine a group of people who want to purchase a phone online and there are people from different regions, different ages, and different budgets. Many of these people are looking for the best phone within their budget, the best phone in terms of performance, the best phone for gaming, the best camera phone, and so on. Everyone is looking for specific and different information compared to others. At this time, it's important for us to do a quick check to see if we have that information that they are looking for, and if not, then we need to think about this first.