I would like to have a small, simple, and relatively inexpensive ceremony. How do you get married at the courthouse, and what is the cost? Also how do I find that info in the state I live in?

Call your local courthouse and speak to them about this. Generally one of the judges will marry you after you get your marriage license. It is not that expensive. Some judges don't charge at all. Call and ask. They love to marry people at the courthouse.