Think of when you go to an NBA game and they give out some sort of "freebie". I would imagine those game "freebies" cost much more than $3000, and regardless of that, with Facebook you are potentially reaching the 1M+ fans where as those game "freebies" might only be handed out to a measly 5K. It seems like a no-brainer to use Facebook to reach 1M+ fans at that price, vs what they traditionally pay for other forms of marketing.
Also, you could easily be selective on what sort of post validates for a $3K (post) promotion. Not all posts are worth promoting to every one of your fans, doing so would just weaken the brand image (in my eyes).
People feel betrayed by a company desperate for new revenue.
I guess any kind of prepaid arrangement (with some reasonable quotas, or upfront costs + small price per post) would be more manageable.