You can see from Heritage auction sales that price boom happened around 2005 where it went from 600 to over 3600 in recent auctions. http://coins.ha.com/c/search-results.zx?N=51+790+231&Nty=1&Ntk=SI_Titles&Ntt=1923+chervonet
Sign up is free and you can even use paypal now IIRC correctly. There is lot of variation in prices MS65 seems to have fetched 5,750.00 and that was couple years back.