The net worth of the entire site is probably somewhere in the $10,000-$20,000 range based on ads and page views. Athens is making a pretty penny off of this site, but it's not like he can completely financially support himself based on the revenue (Then again, once you throw ATRL+ into the mix, the site becomes that much more valuable, because you cut out the middle man (ad agencies) and that $20 per 3 months goes directly into the owners pocket.) If I was a business investor, the most I'd offer for the site would be $25,000, but I would be expecting to incur costs for server maintenance to finally fix the problems existing.
In terms of paying per month, I doubt I ever would. Now that I'm in college, I don't use ATRL as much, and charging a veteran user who's been here for 4 years somewhere in the $5-10 range would be ridiculous (but the owner would make a ridiculous amount of money, so

) If it were $1 a month I'd probably pay it, but that's still $12 a year to access a site I rarely use anymore (but for others that $12 may seem like a deal)