where does the traffic come from?
A quick Alexa query says that 35.8% comes from search engine queries for various searches to include "minecraft level generator" and "aika zero ryona 2", the former of which comes up on the first page on a google search, while the latter did not.
Only one site is linking in - so this is not coming from backlinks. I have a feeling the rest is type-ins.
There is content on the site, so this isn't just a domain name for its keyword value.
Assuming the average revenue ($700 - right within the $600-$800 range as stated) has been earned consistently, I would place a value of about USD $40,000 on this site, depending on how the traffic is converting in terms of ads.
The only problem is, while the name is generic, it's not generic in such a way that just anyone could use it. Something credit card, insurance, travel, or financial related would be in high demand as affiliate programs can make whoever is running a site on that domain a pile of money. And anybody who has $xx,xxx to spend on a domain name will look at such names as the ones I had mentioned first.
My advice would be to keep adding content, maybe add a twitter channel, create a brand, build a buzz. I think that you've got a great site concept, but it just needs a little bit of polishing, and you could even turn this into a $xxx,xxx site with some hard work.