You can find out just how much your laundry is costing you in utility bills by using an online cost calculator.
The Laundry Cost Calculator uses a dozen drop-down menus as variables to come up with the final number. It displays the final estimated cost per load, cost per month, and cost per year, based on water/power/gas usage needed to both wash and dry your clothes. It's not exactly pretty, but it's thorough, and it allows you to calculate two different scenarios at once for comparison.
If you've got your most recent utility bills handy, you can use the rates detailed in them to get the most accurate estimate out of this calculator. The numbers might just make you think twice about washing your jeans after every wear.
How much does it cost to run a washing machine? [Saving Electricity]