A valuable 4 letter would be a strong acronym, a word, or something pronounceable. YEVN isn't any of those, imo.
But, four letter .COMs are somewhat unpredictable. I've seen some crappy 4 letters sell for $xx,xxx, and also have seen decent 4 letters sell for $xx.
On a reseller market, maybe $xx-xxx. To be honest, I've seen better ones go for $xx on NP.