Hobonichi partners with a lot of high-end designers, so they’re offering luxury brands to many kinds of customers around the world. They also make sure to include more affordable options in the lineup because the Hobonichi Techo is meant to appeal to everyone-everyone. (If you look up other Henry Cuir products, for instance, you’ll see that all their brand-name products are expensive luxury items.)
So the affordable Colors covers, for example, are all Hobonichi original products, which is why they cost less. The prices start going up when they’re not covers designed by Hobonichi, but partnerships with other companies like ARTS&SCIENCE who are basically offering their designer product through the Hobonichi Store for use with Hobonichi’s book.