The Leavitt machine cancels were used from about 1877-1885 but were at the most popular 1881-83. They were used mostly on the postal cards as the early machines jammed and often damaged regular envelopes. They were used in most large volume areas with the most common being Washington, New York, Boston, St. Louis, Providence, Hartford and Philadelphia.

Type B (often confused with the hand duplex) value $60-$250. Clear markings with complete dial and killer are on the upper end of value.

Type C value $25-$150 Clear markings with complete dial and killer bars are on the upper end of value.

Type AB value $100-$400 Clear markings with complete rectangular dial and killer are on the upper end of value.
Edit: the value of the postal cards themselves are minimal.
Here is one more

Type D value $40-$150 Clear markings with complete dial and killer are on the upper end of value.
The Leavitt machines were used in 22 cities
Washington, DC
Hartford, CT
New York, NY
San Francisco,CA
Toledo, OH
St. Louis, MO
Rochester, NY
Philadelphia, PA
Newark, NJ
Baltimore, MD
Cleveland, OH
Kansas City, MO
Dayton, OH
Buffalo, NY
Chicago, IL
Indianapolis, IN
Nashville, TN
Norwalk, OH
Louisville, KY
Providence, RI
Detroit, MI
Albany, NY