Looks like coins in F-VF condition are pretty reasonable about $10-20.
And I see it's a half-dollar, which was a pretty good pallette on which to work. I really admire the coin designs of the early part of this century.
I did some looking to see if I could augment the purchase with a Davis coin, but it is not readily apparent that more than a few exist, or that any are for sale:
Although the paper notes of the Confederacy are the well known pieces, the coinage is not as well known - for a long time, by even the most generous of definitions, the total coinage bearing a Confederate legend amounted to no more than $2.12.
The Jefferson Davis Dime certainly seems a rare piece.