You can fly and run but cant walk you can be saved but not stored and you can be bought but not sold?

The answer to the riddle is "time." Time can be perceived as flying by or running out, but we cannot physically walk through it. It can be saved in the sense of making the most of it or managing it wisely, but it cannot be stored in a physical form. Lastly, while you can buy time through various means (like hiring help), you cannot sell it.