Financial advisors caution against overusing credit cards, and with good reason: Those high-interest payments can be outrageous!

But for those with financial willpower and the ability to pay their card balances in full every month, here's a tip: You can actually use credit cards as a way to EARN more money! That's right: There are ways to pay absolutely nothing out of pocket and get credit card companies to pay you.

Here's why I opened a Discover Card account and how I've been using it over the past 12 years to make more money:

Earn automatic cash back bonus awards. Discover practically invented the cash back bonus award for purchases made with a credit card, and they continue to offer actual cash back as opposed to the confusing "points" system or "mileage" system offered from other cards. Cash back ranges from 1% to 5% based on the purchase (their different card options have slightly different perks). I've had a Discover Open Road card for 12 years, and I routinely receive $100 to $125 in cash back annually for charging $600 to $1,000 each month on my card (I pay off the balance before the beginning of each billing cycle in order to incur absolutely zero interest charges).

Sign up for the optional double cash back bonus awards. In addition to routine cash back awards, Discover Card offers many "double cash back" events throughout the year for seasonal spending or holiday events. The categories are general (grocery stores, restaurants and gas stations, for example), so I can actually get paid for the shopping I would already be doing. This October, the double-cash back award is for 2% back on telephone, television and internet bill payments made with a Discover card. A pre-Halloween promotion is also available this month: Every purchase made on Oct. 26 earns 2% back! Additionally, certain cards earn 2% to 5% cash back for purchases made at various vendors throughout the year (for instance, I get 2% cash back when I fill up at the gas station using my Discover Open Road card).

Exchange cash for greater merchandise credit. Accumulated cash back awards can be redeemed for cash or statement credit with Discover, but they can also be turned into more money through partner gift cards. I can exchange $20 in cash back credit for a $25 gift card from such diverse vendors as Ace Hardware, Bath & Body Works, and Chico's. Turn $20 into $40 with some vendors such as Mrs. Fields, Samsonite, Enterprise and FTD. And $40 can become $100 at Hyatt hotels. What awesome returns!

Get rebates for online purchases. Sites like eBates are nice for earning an easy rebate for online shopping, but nothing can beat the deals for using When I shop through this site and use my Discover Card to make a purchase, I can earn bonus cash back awards ranging from 5% to 20% (and sometimes more!). In August, for instance, ShopDiscover was offering double bonus awards for online purchases made through clothing, shoes, office supplies, and other school-related sites. My 5% cash back for shopping online at Target jumped to 10%, and the typical 10% back for online shopping at The North Face jumped to 20%! I received a nearly $25 monthly statement credit in August because of that back-to-school promotion. I could also use my regular coupon codes within those sites for additional discounts, so the savings really added up!

Don’t pay for budgeting software. Each month, my monthly expenses are broken down in an easy-to-read format via Discover's online Spend Analyzer software. I can track my expenditures and see where I need to tighten my spending. My statements are also electronic. I'm not paying for expensive online budgeting software, and I'm not wasting time entering this information myself.

Earn more money through a Discover Card savings account. Discover Card offers an online savings account for customers (ranked "Best Savings Account" in 2011 by Money Magazine). Currently, the account offers an annual percentage yield of 0.80% (the national average for savings accounts is a mere 0.12%!). Through November they are also offering card holders a $25 cash back bonus award for opening an account (you must keep a minimum balance of $10,000 until Dec. 31, 2012). To get this offer, you must have a Discover Card  and use offer code OSAEM25912.

Get surprise perks. This spring, Discover sent me a free sample of Starbucks VIA instant coffee and a coupon to use at Starbucks (buy a VIA pack, get a free grande hot beverage). This was simply a "thank you" offer for being a card member. I've also received some awesome travel offers, such as hotel credit and "Book a Night, Get a Night" deals. I haven’t seen high-value deals like this advertised elsewhere.

By carefully using my Discover Card each month for purchases and being mindful of the payment due date, I'm able to turn money spent into money earned!

 This is a guest post by Audrey from Texas
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How to Earn Money with a Discover Card