Play Money chips are designed for entertainment, as well as to help beginners and intermediate players get familiar with poker rules, tournaments and cash games. As the name implies, Play Money chips have no monetary value, and cannot be withdrawn, sold or converted into real money.

To answer briefly, no, you can't legally sell play money on PokerStars.

Places such as Global Poker, PokerStars Play, and the World Series of Poker all offer free ways to play the game of holdem.