The coronation medal in our picture comes from York Coins in Red Hook, NY USA where it sold for $400 US dollars -- a good price for such a beautiful specimen. The medal also comes in copper which would sell, in the same condition, for slightly less than York's silver piece.
Another specimen was sold in December 2010 by Rare Coins and Tokens for just ?110 GBP (about $170 USD). Their medal was not as nice as the one in our primary picture.
The year is 1727 and the subject is the coronation of King George II on October 11th. There is a decent collector following for coronation medals worldwide. Most of these medals are very beautiful works of art.
The aforementioned prices allows us to at least give some ballpark estimates:
average circulated: $250 US dollars approximate catalog value
well preserved: $500
As always, worse condition means lower price and better condition means higher price.
A reputable dealer like York would probably buy this medal for about one-half of its catalog value. This is a typical markup for all types of collectible coins.