I just went to my account and added it up.
I've been a member for less than 6 months I think. So far, I've spent about $2 of real money at Eden and received about $600 worth of product, including free review items and items paid for by Eden Points and Eden Cafe / Lit gift cards.
I really really hope I've contributed $600 worth of content to the site in that time.
It's certainly been a wonderful experience, though I don't think I'll keep up the pace I was at when I first joined and was so excited about the possibilities. I was trying to max out on what I could earn at first, but now I've settled into a more rational and sustainable rate of writing articles and reviews.
Thank you, Eden, for giving us such a wonderful community and so many opportunities.