The answer is free spins are both a bonus you might find at a PA online casino and a bonus feature you might find on a slot at a PA online casino.
Most of the information on this page is about converting bonus offers at PA online casinos into free spins, rather than the free spins bonus round found on many slots that allow you to play for free. Either way, we're talking about playing with the house's money and spinning away at your favorite slots without risking any of your hard-earned cash.