Car dealers have many ways to get the most out of each car deals and loans.

If you're not careful, you could end up spending more money on buying and subsidizing a new car or truck than you really need. It's a waste of money for anyone trying to build financial security for themselves and their families.

Dealer Tip # 1: Take advantage of your lack of information.

Without a clumsy shopper, sales people like it best. You can't bargain for the vehicle when you don't know what the price should be.

Before heading to the dealership, visit Edmunds.com and Kelley Blue Book to find the average transaction price for a car or truck to buy.

Or add the Edmunds or Kelley app to your smartphone and then enter the other options listed for the model, interior level, equipment kit and window sticker for any car in that lot.

Either way, you'll know that the person buying the car is actually paying for the ride you're considering, which is often a few hundred dollars or even thousands of dollars less than the suggested retail price shown in the window.

You want to be a smart shopper and pay a little less than the average transaction price.

Dealer Tip # 2: Take full advantage of monthly payments.

Salespeople often ask potential buyers what is the maximum monthly payment they can afford.

With this number, they will calculate the maximum amount you are likely to spend and meet the monthly payments by holding off the loan for as long as possible.

You'll then see cars and trucks in that price range, which is usually higher than what you want to spend, and you can rest assured that better rides are within your budget.

Let's say you're here to buy a compact car, which costs about $20,000, but if you just pay, you can afford $450 a month.

The salesperson immediately realizes that a 60 - or 72-month loan will allow you to buy a $25,000 midsize sedan while keeping your payment at around $450 a month, and that's how he or she will try to sell it to you.

Higher sticker prices and longer loan terms mean more money for dealers.

Use the 20/4/10 rule to see what you really can afford.

It says you should put down at least 20 percent of your vehicle, finance it for no more than four years, and don't spend more than 10 percent of your monthly income on car expenses, including bills, maintenance and insurance.

Dealer Tip 3: Apply a financial fee bonus.

You've chosen the car you want to buy, and now the finance manager is searching his computer for the best deal on the loan. There's no need for the dealer to tell you the cheapest loan you're eligible for, and you can legally add a few percentage points to the interest rate yourself.

Suppose the bank or financial company says you are eligible for a 5% loan, but the finance manager tells you 7%.

On a $22,000 five-year loan, that extra 2% will add $1,277 to your payment. The lender bargained with the dealer. It collects the excess money, keeps half for itself and sends the other half back to dealers.

Although perfectly legal, the Justice Department and the Consumer Financial Protection Bureau have been investigating whether dealers and lenders tended to discriminate against women and minorities by increasing the markups on loans.