savitale, Shortly after I bought the coin several years ago I stumbled on 2 raw examples equal to my coin priced at $40 & $45. The ancient coin market was in a slump then but has since revived & high quality coins of Constantine I have shot up. The whole series of Constantine's coins is vast & complicated. You could spend a lifetime trying to assemble a type set of his coins from all the different mints . A pair of German authors, Alten & Zschucke, have documented 179 different varieties of my coin type & the coins of his two sons, from the Trier Mint alone !
coin_nut, You're right on . Our money isn't much different than Roman money; it's backed by nothing & the longer you hold it the less it's worth .
My big question would be: "Do you like the coin?" If so, you did not overpay. And yes, I have overpaid for a coin. And, I was/am happy with the purchase--sometimes. Over all, I am happy with my decisions. For me, collecting, and studying coins, is a learning journey. Nice coin! Happy hunting.