None of the silver Roosevelt's are hard to find or expensive. If you settle for circulated coins, you can probably get all of them for silver value. In uncirculated the 1949S, 1950S, and 1951S (in that order) are the most expensive. Some dealers ask $50 or more for 1949S for raw coins that they graded as MS63 (for example). I think that is too much to pay. I am still looking to complete this set in uncirculated without paying too much.