At the end of December, the Bit’z Kids children’s store at 275 Greenwich put its entire inventory on sale at 70% off. “Not yet,” replied the clerk when I asked if it was closing. With the store finishing up another end-of-month sale (70% off everything through today), I went back in again. This time, a different answer: The store, which opened in 2010, is closing at the end of March. There’s another Bit’z Kids on Houston between W. Broadway and Wooster, as well as one on the Upper West Side.