(I) don't know where this tip might fit on the site, but I had an experience recently that is going to blow a big hole in my budget. I got caught speeding. Even though the trooper was merciful, court fees alone are 90 dollars. Speeding isn't worth the risk in safety and cost.
Once upon a time, many years ago, I attended a personal finance seminar where the speaker claimed to buy all of her clothing second hand, use generic foods and pay off her credit cards on the first of every month.
You know what stuck in my mind? She recommended using the library extensively instead of bookstores, but she then went on a tangent about library fines. It seems that the librarian knew she would eventually return her books and so wouldn't charge her the replacement fee on her books no matter how long overdue they were.
After all these years, I shake my head in wonder.
Why bother to pay attention to generic apple sauce for ten cents less than a name brand if you're going to pay the library two cents a day for three books for a month, because you won't take the trouble to return them on time?
What about other times when we cost ourselves money?
Times like when we have to pay late fees on bills when we could have paid them on time, or administration costs on insurance premiums because we pay them each month instead of each quarter or half?
Parking tickets? Overdrawn accounts at the bank?
Sometimes it's what we don't do that costs us the most money.