Is Kim Kardashian worth the $1 million that she purportedly demands to endorse a product? Reuters

Kim Kardashian's minimum rate to endorse a product is $750,000 to $1 million, RadarOnline reports. The entertainment and gossip website uncovered secret business emails between Kardashian’s reps and a firm that wanted Kardashian to promote its brand.

The "Keeping Up With the Kardashians" reality TV star's demands didn't stop there. In addition to the fee, Kardashian demands travel-related expenses -- Kardashian-style -- to be paid as well, including first-class airline tickets for her and her entourage, luxe hotel accommodations and payment for a pre-approved "glam squad," including hair, makeup, stylist and manicurist. Oh, and Kardashian, whose estimated net worth is $65 million, according to Celebrity Net Worth, wants a per diem. Discount sibling, Kendall Jenner, reports Radar, is only demanding $500,000 to $1 million, according to the Kardashian rep.

When it was reported in 2010 that Kim Kardashian was being paid $10,000 per tweet, Yahoo’s principal research scientist Duncan Watts, used hypothetical models to determine if that amount was worth it in an AdAge report. His conclusion: No.

"If I had a fixed budget," Watts said, "I could get more value from a small amount of very influential [influencers], or a lot of smaller influencers, on Twitter," Mr. Watts said. "If you recruit enough people who, on average, influence just one other person, you could get a much better return on investment if you aggregated them and altogether paid them a tenth of what Kardashian gets." The "many-to-many connections," he argued, spread influence in more productive ways than through a few highly-connected people such as Kardashian. People might not be paying attention to the retweeters of Kardashian's now 24.6 million followers on Twitter for example, whereas he says they are paying attention to influencers.

The question of if Kardashian is worth it depends on several things, according to brand strategy consultant Eli Portnoy of Miami’s CultureRanch, including the goals of the brand that is considering paying her substantial fee and whether the negatives of her "antics" that may accrue around the promoted brand are worth the attention and awareness that she can drum up.

"Kim Kardashian is the perfect example of a non-celebrity celeb. She's D-list and is the epitome of a person of questionable talent that people might be fascinated by but do not love. Her polarizing reputation may overshadow the awareness she'll bring to a brand that wants attention, especially since the attention she brings is largely not positive," says Portnoy. "People also know she will promote anything for money."

The smallest amount of Kardashian's annual income comes from social media, according to a recent Forbes report. According to Forbes, Kardashian's formidable earnings come mostly from public appearance fees such as club and shop openings and events than for any of her TV work. She also takes a cut from the Kardashian Kollection, a clothing line sold at Sears with her sisters; the Kardashian Beauty cosmetics line; and DASH, a small chain of clothing boutiques that sells the small, tight dresses that she and her sisters wear.