1) Micropayments. The key to charging for content is DON'T charge for everything, just charge for some percentage (10%; 1%, for example) of premium content.

2) "Recommended donation." Like a museum. People can give nothing if they like, but suggest what they should donate. Keep track. Make them register for more than the most basic form of content. Then cookie them and keep a running tally of what they owe. Say, 1 penny per page view. After they've viewed 50 or 100 or 500 pages, remind them politely (e.g., with a page intercept, a flashing notice in the corner, an email) that they are obviously a regular reader and you ask your regular readers for a donation. Sure, many, or perhaps most, will ignore it, but in all likelihood a significant percentage will give something. Some will give what you ask, some will give less, some more. In any event, you'll earn more than you earn now.