Where to buy Nike Joy Ride Shoes?

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I have this pair of grey Nike Joy Ride shoes and they are so comfortable, I can wear them all day! But they are getting a bit worn out, so before I start to teach in two different schools, I thought that I would get a new pair. It seems, however that the style has been discontinued. Does anyone know of a place online that I can buy a new pair? I would settle for grey or black, not white. Thanks in advance.