Taking a few minutes to explore the marketing ideas behind these sites is time well spent:
Fiverr.com: What would you do for $5? Can this be a good source of leads or even a good publicity stunt for your biz?
Fangager.com: Reward your fans and followers with points for interacting with you socially online.
Groupme.com: Send group texts.
Resource page: 101FreeMarketing.com
Do you have any to add to the list? Visit the resource page and tell us what you think.