Thank you for contacting Mearto with your appraisal inquiry. Based on the photographs and description provided, the subject of this appraisal is a subset of a stamp collection consisting of 38 first day covers of United States postage stamps from the early to mid 1950s, 1 stamped non-postmarked envelope from the same timeframe, and a Grossman Stamp Company sheet of US presidents and famous figures. The covers comes from the early to mid 1950s and the Grossman sheet from the mid-1960s. According to the current owner, the collection was acquired via inheritance. Concerning this particular subset of the inherited collection, these pieces are well organized. Unfortunately the first day covers have book values of approximately $4 to $5 each cover and the Grossman sheet can be found on online auction sites for about the same price. In consideration of the factors noted, a Fair Market Value (pre-auction estimate) of this portion of the collection examined would be estimated at $125 to $150.