There are a few things to look out for while applying for a marriage license in Colorado. First, the marriage license expires 35 days from the day it was issued. That is not a large time window, so make sure to plan accordingly! Also, marriage licenses cost $30 in every county in Colorado. Not every county accepts credit cards. Some counties only accept exact cash. Make sure to check to see what your county accepts before going into the office to file for your marriage license (as no one wants to go twice)!