The cost of a patent can vary widely depending on, not only the complexity of the invention, but also the intended market. The most expensive patents are international patents, which can run up to $100,000 or higher.Domestically the costs can be $10,000 or above.atent applications involve lots of text and drawings, even for simpler inventions. The first step in the patent application process is to file a non provisional patent application, which involves paying attorney fees in the range of $5000 to $15,000 or more, depending on the intricacies of the invention.