Bargain plants. Many stores clear out plants that are not doing well, and will mark them down to half price, sometimes less. Look to see if the plant is basically still there - a reasonable amount of leaves that are still green. Generally all that has happened is that the plant has outlived the pot’s resources. If it is a potted plant, meant to stay in the pot, just fertilize it a little to revive it. If it is a garden plant, putting it into garden soil should do the trick, though it will likely drop blossoms or any fruit that is on it when you  transplant. Be patient, it will most likely come back.