Here's how I did it:
1) Bought the living social deal via my Chase Ultimate Rewards portal (3% rebate = $1.49)
2) Used promo code USA10 for a purchase of $49.50 (10% off $55)
3) Posted my referral link here, on Facebook and other forums
4) Three people purchased the deal using my link ---> $49.50 purchase refunded by Living Social!
5) Now I have a free 1 year Costco member PLUS a $20 Costco cash card, a 48 pack of AA batteries I have no use for so I will sell on eBay for about $17-18, and the $1.49 rebate ---> I'm getting paid about $40 for my Costco membership
The deal also includes a coupon for a free rotisserie chicken that I have no use for. I'm a vegetarian and don't want to sit in a car smelling like chicken so I'll probably give it to a friend or coworker. There's also a free case of bottled water coupon but I have resuable water bottles so I probably give that away too but someone else could end up netting about $50 for a membership if they would want those items.
Caveat - this deal is for NEW members only.