RuLaLa is offering a nice little deal to new invitees. They are giving you a $20 credit just for signing up.
You don't have to use the credit today either. To be perfectly honest, I find them on the expesive side of the invitation only shopping sites but you can find some good deals. I through this jewelry case from Spartina was adorable and it is $19. You will at least want to sign up and get the credit because they will not be offering it for long and you have to go through THIS LINK to get the credit .