An NCV chip would be used in a tournament for example, where it has a value of sorts, but not a cash value. A free play chip is usually used as part of bet. For example, you use a $5 free play chip along with a real $5 bet in blackjack. If you lose, you lose both chips. If you win, the dealer takes your free play chip, but pays your bet off with $10, $5 for your real bet and $5 for the free play bet.

Greg