Is a provisional patent the cheapest type of patent? 2 Answers as of July 30, 2010

Obtaining a patent is quite expensive, requiring an experienced patent lawyer or firm to do it right. Cost varies dramatically with the nature and scope of the patent, and the work necessary to properly do all the documents. For some simple hardware item, maybe a few thousand. For high tech science, many times that. There are companies that claim to help you file, or help you market your invention, but by very careful to avoid both scams and being ripped off. Do your research and get solid recommendations from other people in your industry.

At $1000-$1500, a provisional application is indeed the cheapest way to begin the patent process, but it comes with limitations. While filing a provisional application allows the inventor to claim their invention is "Patent Pending," the inventor must also file a utility application within 1 year of the filing date or their application will be abandoned and they must start the process over.