Some gas stations place a large hold on your credit or debit card – anywhere from $75-$100 – when you pay for gas at the pump, while others charge only a cursory $1 hold fee, regardless of how much you actually pump. In both cases, the actual charge isn’t posted until days later. If you go shopping in the meanwhile, your available balance will reflect the amount held by the gas station. If this is more than the amount that you actually spent, you’re safe. But if this amount is less, you can run into problems.

For example: You fill up your gas tank for a modest $50. The gas station, however, only puts a $1 hold on your card. You check your balance at the ATM day later, expecting an accurate statement, but in reality, the $50 has yet to post to your account. Thinking that you have more money available than is the case, you stay within the balance shown on the ATM statement, but overspend because the $50 you spent on gas doesn’t post until 2 days later. Your bank will likely charge you at least one overdraft fee when the gas purchase finally posts to your account, and you may be charged more than one overdraft fee if there are pending transactions at the store which were approved based upon the erroneous balance.

Another example: If you rent a car with your debit card, most companies place a hold on the card equal to the charge for renting the car. However, this hold often expires within a week, so if you rent the car for longer, the initial hold on your funds is released. When you check your balance several days later, it would appear that you have money to spend, when in reality the rental charge hasn’t gone through yet. When you take the car back, the company may not even charge your card until the end of the day’s processing, at which point it may be declined or (because of the previous hold) you may be charged overdraft fees retroactively.

These types of overdrafts can happen in any instance where a temporary hold is placed on your card. If the transaction is later declined and you avoid the bank fee, you can still expect to pay fees from the merchant, who will then be forced to track you down for payment. The only way to avoid this type of scenario is to keep track of which charges are pending and which have actually posted in your account. In short: you can’t trust the balance inquiry from the ATM to be accurate if you’ve recently made these types of purchases. Other ways to avoid the risk:

1. Don’t pay at the pump. Go inside and pay – when you pay inside the gas station, the charge typically reflects what you actually spent, rather than an arbitrary hold.

2. Keep track of the hold amount, and ask to pay in advance if possible. Some rental companies and hotels will allow you to pay the fees from your debit account up front. Keep in mind that if you rent the car or stay at the hotel for longer than the original agreement, a hold will still apply.

While banks can’t let you spend money you don’t have if you don’t opt into overdraft protection, the bottom line is that you still have to be wary in order to avoid a hit to your wallet and your credit. Take the time to confirm that the money is really there before you spend, and you’ll save yourself a lot of unnecessary fees.

And it isn’t just pay-by-phone options that can cost you. Some utility companies charge fees when you use credit cards to pay, and if you cannot pay off the credit card in full each month, you are effectively paying interest on fees charged to pay a bill, not even the bill itself, which is a definite waste of money that could otherwise be used to help balance your budget, increase your savings, or even add to an investment.

So how best to avoid these types of fees when you’re trying to repair your credit and pay bills on time? The easiest way is the old way – write a check, be sure that you mail it in time for it to arrive well before the due date of the bill. However, for many people who are living paycheck to paycheck, this may not be an option at first. Another method that can work just as well is to set up automatic bill pay through your bank. Because many banks offer bill pay for free when you have a checking account with direct deposit, it can be simple to ensure that your bills are paid on time without having to pay additional ‘convenience fees’.

Another way to avoid fees when paying your bills is to enroll in automatic payment. If you know you won’t have the money available before the due date in order to mail a check, but will have the money available on the due date itself, you can oftentimes set up an automatic bank draft or charge to your credit card that does not incur additional fees. However, you should be careful with these types of arrangements if you are still trying to manage your budget – over the limit fees on your credit card or overdraft fees on your bank account can wreck havoc on your careful spending plans.

Regardless of which method you choose, it pays to be informed of exactly how you are managing your bill payments – repairing your credit shouldn’t cost you more than it has to, and with proper planning, you will be well prepared to take care of your bills in a manner that is both convenient and free. Always ask if there will be an extra charge when you pay over the phone, and be prepared to explore alternate payment methods that will let you meet your financial obligations without charging you extra to do so.