First - Never ever trust an Amazon Marketplace price. Run a search on ebay and then filter for sold listings to get an idea of what an item has been selling for recently. And even then be careful. The "buy it now" option on ebay leads to a degree of price inflation; there are people out there with more money than sense ... or maybe they're poor but have no sense.
Second - If you're going to shop ebay for
LotR minis then definitely carefully check the
GW site to see if
GW is still selling the miniatures you want in some form and
GW's price. I have been watching ebay for some
LotR stuff recently and I see people asking for and sometimes even people buying models that are in print for above what
GW is asking. Sometimes this is a result of people preferring
OOP metal miniatures to Finecast but sometimes it is just a scam.
Third - You might find this unofficial catalog of
LotR minis handy, I know I sure do. God bless the person or persons who put it together.
http://www.miniman.hu/pdf/unofficial_lotr_collectors_guide_6.2.pdf