I saw a post about the Text Link Ads Link Value Calculator over on Darren's ProBlogger site. Apparently the calculator is an estimate of market prices for text links (they have a disclaimer for their tool: "does not always reflect the prices of Text Link Ads inventory").

According to the Link Building Blog, the calculator factors in:

• Traffic of your website – the lower the Alexa ranking, the higher the price.
• Link popularity of your website – the more links (and more quality links), the higher the price.
• Theme of your website – there is more demand for some themes than others.
• Number of links to be sold – the fewer the number of links on a page, the higher the price.
• Sitewide or single page placement – "sitewide" vs. on a single page of your website (slightly more value given to links that appear sitewide).
• Location on the page – more value when the links are placed in an area where they have the best chance of being clicked.

I was playing around with the tool and I learned that the best paying category is gambling and the lowest is other. I ran the the tool for two different sites and the ratios were the same. Here is the breakdown:

As you can see, text links on gambling sites are about doubled the price of web and technology sites. Of course, that's a ball park figure and doesn't reflect what's in inventory.