The only optional costs for my customers when I owned small motor control company's were on their site training
Included in the quoted price were spare parts, instruction manuals (if they wanted more, yes additional cost), on site instalation till certified, basic training and 1st yearly inspection
Industrial, so they knew more about the product than general public...but Turtle, Grit & others are so NOT 'general public'...
Some of our competitors did charge for some of these basics...why we were awarded
Plus, we did NOT try to tell the customer what they wanted...