Hello Oz,
The major marketplace I use is Flippa.com. That's the place I sell all of my websites. You can also try warrior Forum. The price at which your site will be sold depends on certain things:
1. Traffic: One of the things buyers look for is the traffic details of the site. The more the traffic to the site, the more the confidence about money making potentials.
2. Revenue to date: People like to see the proof of revenue you have generated from the site so far and analysis who viable the site is compared to the traffic being pulled by the site. The revenue to date of sales also determine your selling price of the site. Averagely, most sites are sold 2-3 times their revenue realised to date of sale.
3. SEO: The site ranking and positions in search engines matter, not just ranking for one keywords, but other searchable keywords matter.. The backlinks to the site is very low at the moment despite being around since 24th April, 2010 according to the WHOIS details of the sites. Also, the Alexa ranking tells. I can easily tell that there are no much or enough traffic to the site on daily basis. The current traffic rate will be average of 9 - 11 visitors daily.
Others include means of monetization, site age, easy site nagivation, quality of contents and Plus lots more
There are lots of factors that determine selling this site for higher value which you can start to work on at the moment if flipping this site is your goal. So, analysis those points given above in relation to your site data/details at the moment. I will not want to write a report here, I will just keep it simple.
Guess this help!
All the best
Olusegun Balogun