It's very nice and useful website. Nice to have such database. When it comes to appraisal it's hard to give any without knowing stats and revenue. Website itself is not worth much because everyone can create similar website but not everyone can bring traffic to it and make money. So if you are interested in more accurate valuation gives us more information. Otherwise it's not worth much because services such as http://mcjonline.com/www/byfont.com shows zero value because there are no backlinks, traffic and website was recently established.
You are on the right forum then. This question is answered few hundred thousand times already so do your homework and start learning.
I am not forcing to use paid services. There are many threads that specify how and where to build backlinks so you don't need to pay to anyone unless you decided to do so to speed things up.