Kelly her networth is in no way $28 million. Every album she sells, she gets a basis $1. And a dollar or three more depending if she wrote on the album. So let's say she gets $3 per album. She has sold 26 million albums now which equals a total of 78 million. Those 26 million that were sold made about 338 million dollars, around 70-90 for Kelly, around 20 or 30% for the retailer, and the rest is for the producers, writers and label. And then we still have single sales.
It costs a lot to really promote a album, it can cost up to 5 - 10 million dollars. That's why labels can't afford albums to sell lower than 500,000 copies. And that's also why artists gets dropped from labels so quickly.
But besides the album sales, Kelly also has her touring which I think she earned the majority of her money. Especially her corporate events. Kelly takes around 300 - 500 thousand dollars per private event.
I think her net worth is without a doubt near $100 million dollars. No way as **** does Bonnie Mackee have more money than her. Kelly probably made more in her thankful era than Bonnie her entire career
Keep in mind that a single only costs $1.99 and she had a lot of singles from Katy Perry so $0.69 in which she gets like maybe around $0.25 per record sold. Her own album and single flopped and she doesn't tour.
God bless her 2010 look… 
I noticed her arm, too 
). Does Kelly even spend her money on something (besides Taco Bell of course)? And didn't she said something like that she invested money in something? That would make even more money for her. 
Hope you're fine