You should consider selling your own ads.
I am in the same situation only I have about 500mb too much space, it is the transfer I am out of. I have been at 19.**gigs for the last 3 months and now it is picking up more. Even feb with only 28 days was around 19.5 gb. So now I will be paying $45
I just put on openads (phpadsnew) and started selling ads yesterday. I earned enough for 3 months of the voyager plan on the first day
and have not even scratched the surface of my ad inventory yet. Funny thing is though, all I have sold is static text links so I don't even need openads yet.