They say Liza Minnelli, like supermodels of yesteryear, won’t get out of bed for less than $250,000. And, really, why should she. But it turns out she’ll leap gratis from her sleeping chamber for some chopped liver on toast points. Page Six reveals today that the Italian nightingale said, “Oy, yes,” when asked to perform at the bat mitzvah of Charlotte Kassimir, daughter of so-called hair transplant “guru” Dr Joel Kassimir, a friend of the family. The designer pink-and-white crystals that decorated New York’s Marquee club cost $1 million, but Minnelli didn’t charge for performing five songs. “Enjoy being a girl,” she said to Charlotte, but instead of using that as a cue to belt out the famous tune from Flower Drum Song, she added, “because life goes by in a snap.” She should know, but that seems kind of a downer thing to say to a 13-year-old.