Over the last 30 years, the business models of rap labels, specifically the ones that tap into an indie ethic associated with music labels of the 1940s and ’50s, have at times been more interesting than the music produced. Decade by decade — starting with Sugar Hill in the 1970s and including Def Jam, Master P’s No Limit and Cash Money — rap is the one place in music where entrepreneurship has been met with rewards far more consistent and lucrative than other elements of the music business.

Making money, though, has been an overbearing theme in rap for too long. And artists who are breaking away from the cliche are seeing the rewards. T.I.’s singles set back-to-back records as they made enormous leaps on the chart to No. 1; Lil Wayne has led the album sales field; and Kanye West continues to develop as one of pop music’s most intriguing players, his “808s & Heartbreak” one of the top three most anticipated albums of the year.

It’s Lil Wayne’s “Tha Carter III,” though, that has become the standard-bearer for rap in 2008, as it holds the title of being the biggest seller of 2008 at 2.5 million. “Tha Carter III” was released on the heels of Cash Money reupping their distribution deal with Universal Motown, an agreement that allows the label’s owners, brothers Ronald (Slim) and Bryan (Baby) Williams, to hold onto a significant chunk of royalties and publishing revenue as well as the master recordings. (That’s a different scenario from a number of labels: T.I., for example, owns the Grand Hustle brand while Atlantic Records owns the label; Roc-A-Fella, which Jay-Z founded and lists West among its artists, is wholly owned by Universal. )

Cash Money was started in New Orleans in 1991, with Slim taking the role of the businessman and Baby, a rapper and a member of the Big Tymers, to play talent scout. They sold 12-inch singles out of the trunk of their car, losing money until the single “6th and Barrone” by U.N.L.V. did about 20,000 in sales and became their first money maker.

UNLIKE MOST indie rap labels the Williams brothers did not forge a joint venture deal. The sales the label has generated — they say 45 million albums — are the result of strategies.

“When you start taking it upon yourself to guide your own destiny,” Slim said just hours before a party in Miami at which he gave Lil Wayne a briefcase containing $1 million in cash, “it becomes like chess. We had to educate people about our music. Everything we have done has been a hands-on (approach). We stay grounded and focused, try to not wear out our welcome and realize some artists will go quicker than others.”

Strategies, for the most part, relate to release schedules. The strategy for Lil Wayne, however, is a bit staggering: he has released more music than just about any other rap artists and he tours more than most and often performs in smaller venues that sell out in minutes. Along with T.I., he has proved that rap from the South does not have to be strictly Southern.

Rap, Slim says, is a starting point for Cash Money and rather than expand into management, a job he never wants, the label has decided to spread its wings into other genres. Among indies, no label has ever done that successfully with the exception of a few of Motown’s sister labels that ventured into rock.

Finding talent for the pop and rock side has taken Slim and Baby out of their comfort zones, musically and geographically, as they have signed artists from New Jersey, California and London. Their first pop project to come to fruition is from Kevin Rudolf, a 25-year-old singer from Miami, whose first single “Let It Rock” is top 15 at mainstream top 40. It helps that Lil Wayne’s name appears on the label, too, but it also demonstrates the rapper’s crossover appeal — Rudolf’s sound is more akin to Justin Timberlake than anything with street cred. Rudolf’s album, “In the City,” will be released Nov. 25.

“It’s much different,” Slim notes of the pop and rap worlds. “Rap and image go hand in hand — you have to make people know who the artist is. Pop and rock, get a hit record and you’re on.”