Hello Corey, and welcome to Seven Forums.
Quoted from Microsoft:
To avoid interruption, it’s recommended that you and your customers rebuild test machines by using a valid Windows operating system before Windows 7 Beta and Windows 7 RC expire. Windows will automatically notify you that the expiration process is about to begin. Two weeks later, your PC will shut down every two hours. For Windows 7 Beta, the bihourly shutdowns will begin July 1, 2009. The software will expire August 1, 2009. For Windows 7 RC, the bihourly shutdowns will begin March 1, 2010. The software will expire June 1, 2010.
You can see how much Windows 7 will cost and compare features at the link below. Compare Windows 7 Editions
Hope this helps,