I'm running a (small) image hosting site which has been getting a little bit of traction lately (2,000 to 5,000 visitors a day, spikes up to 10,000). It's hosted on Linode and I've already run out of the bandwidth for this month (300 GB). I've experimented with Amazon S3 but that was costing me $5 a day, Linode currently costs me $30 a month. I get a tiny bit of revenue from ads (Adsense and Black Label Ads) but it's not enough to break even.
What should I do? Obviously I'd like to keep running the site but not if it starts costing me a lot of money.