David Cook, the scruffy rocker and winner of the last Idol competition, earned an estimated $2 million since June of 2008. That's a huge boost from what Cook made as a struggling singer-songwriter in Tulsa, Okla., before the winning the Idol crown last May.
Yahoo! BuzzForbes estimates that Cook generated the bulk of his income from the 1.1 million copies sold of his self-titled major label debut album. Cook supplemented his music sales with a live tour and a product sponsorship deal with sneaker maker Skechers.
Cook's final competitor, David Archuleta, has also enjoyed a remarkably lucrative year since making it to the Idol finals. Archuleta made an estimated $1.3 million from sales of his first album and more than 100 live concerts.
Yet for a lesson in how to build truly massive riches, the current finalists should study the brief career of season-four winner Carrie Underwood. The farm girl turned songstress has gone on to a hugely lucrative recording, touring and product endorsement career. Underwood raked in an estimated $14 million last year, enough to secure the title of top-earning Idol alum.
With her carefully crafted Nashville pop, Underwood cultivates a massive audience spanning both country and Top 40 fans. Her debut album, Some Hearts, spent 11 weeks in 2007 at the top of the Billboard album charts. Songs from her second effort, Carnival Ride, got massive airplay on both country and adult alternative radio. All told, Underwood has sold 9.6 million albums and 10.7 million digital downloads, according to Nielsen Soundscan.
Along with producing crowd-pleasing albums, Underwood understands the financial importance of hitting the road. She has played more than 300 shows since her Idol win. Each performance brings in about $350,000 to be split between Underwood and the concert promoter, according to Pollstar.
Underwood has also supplemented her recording and touring income with sizable product endorsement payments. She generates tabloid buzz with her personal life--former alleged flames include Dallas Cowboys star Tony Romo and Gossip Girl actor Chace Crawford--but avoids the personal meltdowns that afflict other young female celebrities, making her an ideal pitchwoman for consumer products companies. Vitamin Water, owned by Coca-Cola ( KO - news - people ), pays Underwood to endorse its beverages.
Jennifer Hudson, eliminated midway through the third season, was the second-best paid Idol alum over the past year. Following the show, Hudson smartly bet her best chance and superstardom would come from work that blends her musical and acting talents.
In 2006, Hudson took a supporting role in the film adaptation of the Motown musical Dreamgirls. She won an Academy Award for the performance and has since scored roles in the Sex in the City movie and Winged Creatures, an upcoming indie flick also starring Kate Beckinsale and Forest Whitaker.
Her movie roles, along with a well-regarded album and endorsements from Gap ( GPS - news - people ) and Avon, earned Hudson an estimated $5 million.
Kelly Clarkson, the first Idol champion, holds the title of most albums sold by a show alumnus. The 27-year-old with the powerful voice has sold over 10 million records since 2003, generating a steady stream of cash. Clarkson's All I Ever Wanted, released in March, is currently at No. 17 on the Billboard 200.
Another popular career path for Idol contestants is taking their voices on to Broadway or on tour with roving productions of popular musicals. Clay Aiken, the quirky second-place finisher from the second season, boosted his 2008 earnings by performing on Broadway in the Monty Python musical "Spamalot."
Taylor Hicks, winner of the fifth season, is currently playing the role of Teen Angel in a national tour of Grease. Hicks has also toured extensively as a solo artist and released two solidly popular albums of bluesy tunes.
Constantine Maroulis, who finished sixth place in the fourth season, is the most decorated Idol-turned-Broadway star. This month, he received a Tony nomination for his leading role in "Rock of Ages."
Still, without a big-selling album, endorsement contract or solo tour, Maroulis fell just short of our list of top 10 Idol alums.
As Ms. Underwood can attest, a multi-platform approach is essential to post-Idol riches.