Should you run out of money, refresh your browser which allows the game to replenish free credits.
Perhaps the most common reason for giving a free machine a try is to test something you havent played before and the benefit of no download or registration.
But what if there was no need to pay to play these games?
All of these games come at absolutely no cost to you, and can be played for as long as you want with no requirement that you ever switch over to real money play.
A great place to get free but quality slots games is in social media applets.