My mother-in-law recently switched from a regular cell phone to a pre-paid phone plan and ended up saving almost $40 a month.
Now, I realize that this won't work for everyone. But it does work great for those who want a cell phone for emergency use only or for those who want a cell phone but won't use it very often.
Others might have more savings by getting rid of their land line and only having a cell phone.
What have you done to save money in this area?