$600+/month Adsense Site with my unique traffic?

I don't feel like I should sell them for how much there usually worth because they barley get SE or organic traffic so how much should I list a site on flippa for that making around $600 with my targeted traffic. Everything is legit and I have stats for last 3 months.
Thanks,
Julien

600*4=$ 2k-3k$ My point of view as no Organic Traffic and 3 months Analytics .