I've heard the reports that she received two million dollars for an interview, but those reports have been denied too.
Along the lines of that subject I would this college paper article intresting.
"Paying to play is suspect "
USC paper the Daily Trojan.
I believe this will be something very difficult to prove or disprove as it would hurt the media outlets credibility to pay for a news story.
I think the real question is where she was getting her money for the treatments in the first place. The treatment were not cheap.
Time Article - “The Octuplets Mom Speaks, and the Questions Grow