Then and than. So close, and yet they are not interchangeable. Use "then" when you're talking about something related to time. "Than" is what you use when you're comparing things.
For example: "Then she turned on the cassette player in her car and played More Than Words by her favorite early '90s hair band, Extreme."
Sara J. sent this real estate listing our way. After we got over how much house you can get for $129,000 in some parts of the country (we live where that wouldn't buy you a closet), we had to shake our head sadly at the ad promoting this home.