The United States Patent and Trademark Office divides goods and services into "classes." For example, "works of art made of wood" is in Class 20, and this is a different class than "Graphic Art Prints," which is in Class 16. The USPTO requires mark registrants to list all of the classes of goods and services that their business will provide. So if your business sells a wide variety of goods and services, it will be legally required to list more classes (and have to pay more government fees) than a business that just sells a single type of good. The disparity in pricing is just a function of what the law currently requires.