Many times people do not understand the costs associated with running a website. They think because the internet is "free" that your site must be free to you as well.
So if you have an established member base - if you explain to them that there are costs associated with running the community. They are usually willing to help you out. My experience is surprisingly so.
And it works even better if you offer special features, perks or recognition to users who support you. Even a different color name or special title will make them feel very special for helping you out.