Banking. Avoid overdraft fees at all costs! This is the easiest to give up money and it will mostly be your fault. By taking the time to balance your checkbook, or keep tabs on your spending, you can easily keep yourself from crossing that dreaded line.
It really only takes a little discipline, but it's something essential. It will also keep you in the good graces of your bank. Bad banking practices can also negatively affect your credit score, keeping you from getting good rates on loans.
Want to try and save a little more? Don't bother with a standard bank saving account.
Trust in the Internet and you will find some of the highest interest rates on savings accounts online. Online banks can afford to give rates as much as 3X higher than that of brick-and-mortar banks, putting more money into your account.
How can they do this, you ask? They don't have all of costs of operation that a brick-and-mortar bank does.
The best example I can give is a grocery store that does not allow the use of credit cards. By doing this, they can affordably lower their prices on products. In this case, Internet banks can increase their percentage rates on their accounts.
If you're looking for an account with a low, or no, opening deposit amount, check out Ally Bank or ING.
As of now, Ally offers $0 to open, no minimum amount required and a rate at 1.29%. ING is $250 to open with a $25 bonus, no minimum amount required and a rate of 1.10%.
Take advantage of your banks online bill pay to save money by not buying envelopes and stamps to mail in payments.