Majnoon: You must not try to invalidate other people's appraisals based on your opinion. This is what appraisals forums are for: To know the value perceived by several people.
A domain MIGHT BE SOLD at a price ONE other person is willing to pay for it, but such price does not necessarily reflect what SEVERAL educated-in-the-domaining-business people would pay for it, or the money they have earned in the past selling similar domains, which are, without any doubt, better indicators of the potential outcome of any given domain intended to be sold.
It's all about statistics and, statistically, we domainers don't usually get $600 for dashed, names, unless the dash is an intrinsic part or a very popular coined term, or the keywords are of super-high demand/revenue. Add the non-dotcom factor, and you kill whatever value it might have by a factor of 60-99%
"Can you get me skin-care.com for $10?"
1) I can hand-register or capture non-dashed dotcoms for less than $10. Then, my appraisal might be $0-$3.
"yes $00 right , I already have offers of $600 for it"
2) Take the offer and run fast.
3) And yes, it's true, most domainers will die without getting an offer like that for similar domains.