I'm assuming you mean Nassella tenuissima 'Ponytails' - you haven't said what you intend to do with it, but I'm assuming its going outside, so plant it somewhere that's free draining but doesn't constantly dry out completely. Keep it watered initially until its settled in. If you're not putting it outside, turn it out of its pot and check whether it needs a larger container. Needs free drainage, so a container with holes is essential and don't leave it sitting in an outer tray or pot in water. Either comb or pull out dead brown parts, or cut it right down and let it grow again. Can be cut in April, and again in Fall.
Hopefully, this plant was in the clearance section only because it needs cutting back and may need repotting - if they cut it back, they're unlikely to get a buyer for it, so its not worth the effort to tidy it up. Either that or its one from last year that they've not tended this spring.