How many 4 number combinations are there using numbers 0088?

Oh honey, let me break it down for you. With the numbers 0 and 8 repeated twice, you're looking at a total of 4!/(2!2!) = 6 combinations. So, you've got 0088, 0808, 0880, 8008, 8080, and 8800. That's all she wrote, darling.