Over the years I've come to see sponsorship as better than advertising. Choose some charity or program you believe in, that's congruent with your business, then promote two for one. Seth Godin explains five reasons to sponsor... I've excerpted a couple below.
Seth's blog: Understanding Sponsorship, 2014-Jan-10 by Seth Godin
2. It might be a bragging rights thing. This means that the sponsor isn't focused on tonnage, but instead wants the affiliation that they can mention to others. Sort of a reverse endorsement. The thing being sponsored isn't a media outlet, then, but a license by affiliation. An example of this might be sponsoring a speaker coming to town. Clearly, the 500 people in the audience don't constitute a useful CPM, but the fact that you did it gains you authority with those that notice what you did.
3. It might be a chance to influence the organization being sponsored. This would explain why big corporations are willing to sponsor political conventions.