I have noticed that people often make decisions that completely undervalue the worth of their time. Let's say you know of a gas station 10 miles away that sells gas for $0.10 less a gallon than your neighborhood gas mart. You think you're beating the system, but let's do a little math.
If you have a 15 gallon tank, you save $1.50 because of this expedition. Well done! However, this 10 extra miles each way takes up 20 minutes of your time. If you value an hour of your time for less than $4.50, you did well. If you're employed, I can't imagine this is true.
In everything you do, consider the value of your time.