A group buy is essentially a type of preorder with some elements of crowdfunding mixed in. Buyers interested in a product pay upfront for a product to be manufactured and then sent to them after completion. This method allows for the production of products that may otherwise be too niche or lack general-public demand. The number of people who buy into the group buy dictate how many sets will be made (generally group buy quantity + some extra sets). These products are inherently limited in quantity and may be difficult to obtain after the group buy period ends.
If you are interested in buying a set of Infinikey Comfy keycaps you will have 3 options: