Valuing Medieval And Ancient Coins

also
http://www.coinarchives.com/
can be useful - but it only gives you the last 6 months (high end) auctions for free.

Also cng can be searched for past auctions
https://www.cngcoins.com/
and they include medieval and ancient.

but there really isn't anything comparable to wild winds for medieval - if someone would like to start one though .....

For the more common varieties I think doing a search on V-coins, then ordering the results into price order and looking for coins that seem like they are about as good as your one.

The thing with ancients are that much of it is in the eye of the beholder, eye appeal, patina, how centred the strike is and how well the details have survived all play a part. I think you are more likely to get an accurate picture by looking at the market rather than looking in a book.

When there are far fewer coins to look at (like with more unusual coins) this technique isn't so good because it is hard to judge the market with a smaller sample size.

You can search vcoins.com
http://www.vcoins.com/en/coins/ancient-2.aspx
for retail prices and there is a second comparable site
MA-Shops.com
http://www.ma-shops.de/antike/index.php5?lang=en
which has many of the same dealers but some different dealers.

Of course, "value" depends a great deal upon whether you are buying or selling, and the venue employed. Auction prices of high-quality coins are best checked at acsearch and cngcoins.