You can join for free and have access to loads of images. The tools are very simple to learn. If you have a decorating project pending, it's a great site for helping you get your ideas clarified in your mind.
Here is a bedroom "moodboard" I did when I was starting to think of decorating my room. That's not my room, BTW, but the colours in this are not far off what I used in the end.
Most of all it's fun!
My user name, if you want to see for yourself, is nugget!
Wow! Without appearing to brag too much, I came 2nd in two of those competitions, but the winners had canvassed votes all over Facebook etc! There was no big prize money involved in those, so I shudder to think what will go on in order to win that prize.