I'm not sure if people will accept this as being a freebie, but it could be.
I can vouch for them, having done it when they got to 4,000 followers.
"With only a few short days to the Oscars can we hit 5,000 fans in time? If you tell your friends about blinkbox and we get to our magic number before the show starts in Hollywood then you all shall be rewarded with a FREE award winning movie rental. With only 240ish away it could be an amazing night for all."