Filing a provisional patent application costs $70 when filing as a microentity (common individual case). You can do it without an attorney (see Nolo Press and others for DIY help).

After filing, the applicant has one year to file a utility application (what most people think of as a 'patent application') based on the provisional application.

The provisional app is never published. If there's no derivative utility app, the provisional sinks out of sight.

I forget the current utility filing fee, but it's a few hundred $ for an individual. Attorney's fees are in the few $K range and worth it if you have a valuable invention.

I’ve gotten them between 500 and 2000 dollars depending on the lawyer.