Price comes from supply versus demand. US coins
enjoy practically unparalleled popularity, and are thus easy to articulate values for. The same goes for most issues of Western Europe, plus many/most Spanish or English colonial coins from before WWII. Indian, Chinese, Korean, Vietnamese, and Japanese coins are also on the rise.
When dealing with obscure collecting fields, rarity seldom guarantees a high price, since many will be content with a type collection only. The market is also over saturated with manufactured rarities; entities like the RCM
and Franklin Mint churning out hundreds of types of "rare" coin with mintages in the hundreds to low thousands - there is too much to collect, so they take a massive hit in the secondary market because most collectors will take a pass on anything less than a steal.
New Sale! Inexpensive classic Greek silver, over 2,400 years old!http://goccf.com/t/323297