How much does a patent cost?

12-15K from the time of disclosure to the time of filing. Then another $12-15K to argue with the USPTO. There are also some costs the office charges which I can’t predict because they change them (usually in October). I can say they don’t tend to go down. After that there are maintenance fees at 3.5, 7.5, and 11.5 years in. Those are also set by the USPTO. International patents cost more because 1) you need to pay for translation and 2) different countries have different fee structures.