Yes you can. In the Poker lobby, 'Play Money' tables can be found in the 'Play Money' tab within 'Cash Games' and 'New Player Zone'.
All players start with 1000 'Play Money'. If you increase your chip stack in a session, the same value will be available when you next come to play.
You can reset 'Play Money' by clicking on ‘My Account’. Then click on the new ‘My Account’ appearing hereafter. Click once on ‘Reset Play Money’.