|Bob Harter, P.E.||If you have a patentable invention - I'll get you a patent.|
Once you obtain a patent, you may need to pay periodic maintenance fees to the U. S. Patent & Trademark Office. They come due about once every four years. To avoid penalties, the fees need to be made within certain 6-month time periods. Do not rely on the Patent Office to send you a bill.
Here's how some pay their own maintenance fees online (within the allowable payment window):