Researching the market price here on TS is probably not representative.
16bit is getting out of fashion for taping. You will find buyers willing to pay more in other communities (head-fi, other rockbox users etc).
Selling price on ebay ranges wildly between $300 to $40, mainly depending on country and shipping options:
http://www.ebay.com/csc/i.html?_nkw=iriver+%28h1*%2Ch3*%2Cihp%29+-%28h10%2Cfor%2Cfuer%29&_sacat=0&LH_LocatedIn=0&_sop=3&_dmd=1&LH_Complete=1&_odkw=iriver+%28h1*%2Ch3*%2Cihp%29+-%28h10%2Cfor%2Cfur%29&_osacat=0&_trksid=p3286.c0.m270.l1313
What decides the market price to a large extent is the distance from the US. In the US, buyers are spoilt for choice and wouldn't pay high prices for 6-7 year old technology. The further away from US you go (from a tax/customs perspective) the higher the second hand market price for this kind of used gear. "Internet maturity", ie the willingness of buyers to purchase from overseas vs. being preferrential to local deals, is another factor.