Single thriftest thing? Selling the "newer" car with a year of payments left and becoming a one car family. This works for us because we live walking distance from dh's work and I'm a SAHM. There are days that I tell him to take the car because I know I won't be tempted to go out shopping if I gave to walk!
Other things that helps- doing cash only (no Cc), talking about our finances every paycheck so we are both on the same page, and meal planning for two weeks at a time. Its the little things that really adds up.
J- adoptive mama to DS (7/11), wife to my high school sweetheart and best friend A(4/02)