A provisional patent application is a document that is filed an inventor that can help protect their idea for up to a year until they decide whether or not to move forward with securing a patent.
The main purpose of filing one of these documents is to establish an early priority date, which in patent law refers to the first date that an application was filed. 
A provisional patent application, also sometimes incorrectly referred to as a provisional patent, doesn't actually result in a patent. Instead, it provides the person who filed it with up to a year to further evaluate their invention to decide whether or not it is a viable product before pursuing an actual patent.
The main benefits of filing a provisional patent application include the following: 
- It allows you to claim your invention, which discourages others from copying your idea. During the time that your provisional patent is active, you can market your product as "patent pending".
- It helps you establish an early filing date, which can be beneficial if another inventor tries to say that they had the idea first. In a dispute, whoever has the earliest filing date gets the patent.
- It gives you time to do further research and market analysis for your product before launching it to determine whether or not it is worth paying the larger expense of filing for a patent.
If you are on a tight budget, filing a provisional patent can help protect your idea long enough for you to gather together enough money and resources to file for a patent the following year. Not only that, but by giving you time to evaluate your invention idea, you can get a better idea of whether or not it is worth investing money in a patent before you file.