10/01/2014 02:57 pm ET Updated Dec 01, 2014

5 Budget Mistakes You Didn't Know You Were Making

Think tracking your spending is all there is to money management? You might notice your debt shrinking and your savings growing, but you could be doing a lot more to fatten your piggy bank.

One of the easiest ways to better manage your money is putting a budget in place. But people make a few common errors when planning a budget. Here are five of these common mistakes. Check them out to see if they're holding you back from reaching your financial goals.

1. Budgeting With Your Gross Income

Your annual gross salary might be impressive -- but as much as 30 percent of it might be going to things like taxes, insurance and union dues. And that's all money you can't spend.

Often, people look at their gross earnings when setting up a budget, not the amount actually deposited in their bank accounts (their net income). If you find that you're getting to the end of your money before you get to the end of the month, make sure it's not because you think you're bringing home more cash than you really are.

2. Accepting Negotiable Bills As Non-Negotiable

Often, we accept paying more for a regular service simply because it's the path of least resistance. However, if you spend 20 minutes negotiating a discount or bundle rate, you might be able to save money for months on things like your phone bill or cable bill. If you have a strong record of payment, you may even be able to reduce things like interest rates simply by asking -- the worst that can happen is your creditor says no!

3. Spending Money Every Day

Whether it's coffee in the morning or lunch with coworkers every workday, little expenses always add up to big spending. This may seem fine if you're living within your means; however, it never hurts to go without spending money every day.

If you're not willing to cut out lattes from your favorite coffee shop completely, consider designating 2 or 3 days a week as "no spend days" to rein in impulse buying habits. If you find you're "accidentally" spending money when you don't need to, leave your cash/cards at home at least twice a week. It's a quick and easy solution!

4. Using Plastic Instead Of Cash

We all love the convenience of debit and credit cards because looking at statements each month is easier than writing down every time you buy something (assuming you check your statement... right?).

Still, studies show that you spend 12 percent to 18 percent more when using plastic instead of cash. Researchers have found that it's more psychologically painful to pay with real bills than with a credit card swipe. So, if you're making this mistake too, consider switching to a cash-only system -- it will leave you with more money to save and invest.

5. Thinking "Found" Money Doesn't Count

Whether it's a $50 bill in a birthday card or money you earn selling items on Craigslist, it's easy to count extra income as "free" money and spend it as if it doesn't count. A dollar is a dollar is a dollar, regardless of its origin, so it's important to treat any extra cash that comes your way as a resource for meeting your financial goals.

They say money can't buy happiness, but managing your money thoughtfully certainly can bring you peace of mind. Following these simple budgeting tips will help you meet your financial goals -- whether it's buying a car or paying off your student loans -- as quickly and painlessly as possible.

SALT is a free, nonprofit-backed educational program that helps every student who wants a college degree to get it in a financially responsible way. On October 7, SALT is sponsoring "Know Your Money Day" at college campuses across the country. Know Your Money Day is dedicated to raising awareness of tools, information, and resources that can help students and alumni take control of their student debt and finances.

This post was authored by SALT contributing writer Bridget Casey. © 2014 American Student Assistance.

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