The winners have been announced!
Last month, "GMA" asked two families, the Porters from Salem, Mass., and the Rhodes from Camas, Wash., to chart their gas use and log their mileage, and find out whether they can stick to a list of fuel-efficient do's and don'ts and save a little green in the process.
They enlisted the help of Phil Reed, a car expert from Edmunds.com, and started cutting costs by slowing down and cutting out unnecessary trips.
Whlie both families sacrificed and saved a lot, at the end of it all, there could only be one winner.
The Rhodes set out to save 25 percent on their fuel costs, and they ended up saving 27 percent.
The Porters, by walking to places they would usually drive to, boosted their fuel efficiency by an impressive 42 percent.
Congratulations, Porters, you've won the "Good Morning America" Frugal Family Challenge.
Meet the families and check out some of their video blogs below.
Kelly Porter, mother of 2-year-old Emma and 10-year-old Alec, knows it could be a challenge.
"I'm the aggressive driver in the family," she said with a laugh. "I tend to speed a little bit."
The Porters have two cars. Tim, 42, drives a Toyota Camry for work and Kelly, 41, drives a Toyota 4Runner to shuttle kids, run errands and take on weekend getaway trips.
On average, they spend about $600 to drive almost 3,400 miles per month.
The Rhodes, a family of six, have three cars. Randy, 53, commutes to work in a Ford Expedition, while Mary, 56, drives a Subaru Forrester for errands and taking their teenage boys to and from activities. Ryan, 25, and Hilary,17, love cruising to school, work or to meet friends in a Toyota Camry.
This family spends around $670 while driving nearly 3,700 per month.
Mary knows they could do better.
"I need to combine trips so I'm not running out, running back and running out again," she said.
To help with their task, "GMA" set the families up with auto expert Phil Reed from the car resource Web site Edmunds.com to help the families cut back by keeping their tire pressure in check, making sure their air filter is maximizing fuel economy, monitoring gas mileage per gallon and changing their driving habits for the better.
"This is going to cut down your fuel consumption by 20 to 25 percent," he said, "which I'm hoping will be about $100 in a month."
For the Rhodes, Phil had specific marching orders for the whole family.
"Randy, you're the commuter in the gas guzzler. It's important for you to watch your tires so you're not sitting in traffic in the big Expedition. Ryan, you're the racer. You have to slow down and avoid tickets. Hilary, you're the hill climber. When you're going uphill, don't step on the gas to climb faster. Be steady on speed. Mary, adjust your schedule so you're not sitting in traffic running errands during rush hour or at the end of the day."
Phil also has general advice for both families.