HOUSTON -

A Whopper is a Whopper is a Whopper, right? The ingredients may be the same, but it turns out the amount you pay can vary widely depending on where you drive-thru.

Consumer expert Amy Davis reveals where you're getting the cheapest fast food in Houston and why.

Local 2 logged a lot of miles and thousands of calories to find out why a Big Mac meal on Houston's east side will cost you more than the same meal about 20 minutes away in southwest Houston.

"Doesn't make sense to me," said McDonald's customer Christina Martin.

It didn't make sense to Local 2 that the cost of a Whopper Value Meal from one restaurant to the next could vary by as much as 55 cents. It's $6.48 at a Burger King on Highway 6 in Sugar Land, but $7.03 at the location on West Little york near Highway 59.

Consumer expert Amy Davis ordered the Egg White Delight and a large Diet Coke at 10 different McDonald's locations;  and we were charged nine different amounts. Our breakfast was the least expensive in the Heights. The McDonald's at 2022 Yale charged us $3.78.  At Bush Intercontinental Airport, the total was $6.04. And at the McDonald's in Katy on Fry Road, the same 2 items cost us $5.29.

"The pricing variances are driven by numerous factors," said Stephen Maeker, a franchise consultant with FranChoice. "The franchisor can certainly recommend, if not strongly recommend pricing, but ultimately, it's up to the franchisee in terms of the pricing decision."

Maeker says it is actually against federal price fixing laws for corporations like McDonald's or Burger King to require individual franchise owners to charge set prices. So why does a Big Mac meal cost you $5.79 on Gessner and $6.48 on the East Freeway near Mercury?

"The two key costs that are gonna drive price is gonna be the occupancy cost and the lease cost," said Maeker. 

Restaurant owners factor in everything from how much they have to pay for rent to how much they pay employees to determine how to price menu items. 

"The bottom line is in the fast food business, if the customer feels that they're being overcharged, they can simply go down the street to the next fast food competitor," Maeker explained.

Local 2 found the biggest differences in prices at McDonald's. At Burger King, we were charged three different amounts at five different locations.

Out of five Wendy's locations we checked only the one on Kingwood Drive charged a different amount; and it was just 24 cents lower than the other restaurants. If you're a fan of Chik-fil-A, you’ll be glad to know the prices were the same at every location we checked.

What we didn't find is any pattern of restaurants in more affluent areas charging more or less than businesses in lower income areas. Still, pricing strategies are something franchisees keep private.

We asked to speak with the owner-operators of any of the more than 300 McDonald's in our area; but they all declined.

To see the full list of all of the restaurants we compared and the prices, click here.