How much is it to get married in a courthouse

That depends on the courthouse. Fees range by locality. Just call your county clerk and ask.

Well what courthouse, and the only way to know YOUR courthouse is to call and ask.

Here in GA, you get your license at the Probate Court, but often it is the Circuit Court judge that does the weddings.

The license ( again here ) without a counseling class is 55 dollars and the judge charges 100 to 125 for the service.

Often the clerk of the probate court has a list of pastors in the area that also do weddings in your home or thiers which is often even cheaper.