Play and earn was the way of earning stardollars back in the days.
First you only got 1 stardollar by day, playing games, but some time later Stardoll came up with a new play & earn with tasks and more stardollars to earn.
When you had completed all the tasks you would receive 5 stardollars and, till a certain time, a token.
This way of earning money was replaced with the arraival of starcoins and the earn starcoins sistem.
The task on play and earn inclued vote for covergirl, rate an album, rate photos (wich was possible at that time), vote for best design and rate outfits ( catwalk contest).