The pattern, "The Mount Vernon" pattern by Lenox, was sold by many fine china stores. This just signifies that it was sold by them. A cup/saucer can sell from $28 to $35 depending on area/if you are a store/customer demand. High end is insurance value.
Completed listings on Ebay show that it was attempted to be sold for $49.95 and $69.95 by several sellers and NONE sold.
Agree totally with Wullie, if it is a gift...then the value is in the "kindness of the GIVER of the gift" not the $$ of the item itself.