Vendors
Vendor
Product
Products are what Vendors purchase when they register. They can be anything from a booth type to an internet connection. Vendors can purchase multiple Products.
Variant
Product Variants allow you to have one ore more variations of a particular Product. Variants could be anything from the size of an advertisement to a sponsorship level. A Variant can have overall limits and per-order limits (min and max).
Variant Price
Each Variant can have one or more Variant Prices. They allow you to have different prices based on the date of purchase if you specify a start and end time.