4 word domain name? how much traffic is it getting? how much are you making from it? Don't get your hops up, without hundreds of daily traffic or thousands of mothly visitors, I wouldn't even bother selling it for much, as 4 word domain names are very common right now.
Sorry for the negativity, but I suggest you to sell it for whatever you can get, as anything above $1 is a great offer! Four words, not fluent-sounding, extremely competitive niche ... The above of course applies only in case it doesn't have any traffic/revenue - if it does then it's a whole different story.