What would you do if the forum had a subscription fee (to post classifieds, etc)?

If your intention is only to make ends meet re: running costs, what about a '£ made, £ needed' for the month, like they have on some torrent websites? I think fostering an environment where donations are more prevalent might be a better idea for the moment. Maybe there could be some kind of league table of donators, or donations are made more public, to make it more of an incentive?

I like this idea alot. As lpg and others say I think a payed membership would alter dynamics.

A graphical village fete style bar / thermometer, reset every month (showing negative balance if deficit from previous month exists) showing how far off of the monthly cost we at all times. Watch it rise through out the month, may be something to automatically raise the profile/ "notice-ability" of the bar if the required amount has not been raise 3, 4 , 5 whatever days before deadline. Any surplus money can be put aside as a buffer for any repeated negative moths or into profit.

Keep extra money raised via other methods as a buffer or as profit or whatever you want.