~Isaac Powers, 22 April 1728
Many families of means in colonial Boston owned slaves, and even ordinary tradesmen kept slaves as well as indentured servants to help with their businesses. Slave transactions were completed with regular bills of sale, and were witnessed, signed, and recorded like the sale of other property, such as real estate. The average price for a slave in the seventeenth century was between £20 and £30 sterling; in the eighteenth century it was higher, and varied, but averaged about £40 to £50 sterling (Greene, 318). Typical bills of sale for slaves are Andrew Boyd to John Chandler for the slave Dinah (1769), Malachy Salter, Jr. to Capt. James Dalton for a slave (1749), General John Fellows to Theodore Sedgwick for the slave Ton (1777), Isaac Powers to John Hancock for the slave Jack (1728), Nathaniel Brown to Elizabeth Cabot for the slave Phillis (1768), William Waitt to James Dalton for the slave Peter (1747), and William Richardson to James Dolbeare for the slave Loran (1732).
In some cases, sales agreements of African Americans contained special clauses or variations. Patience Hatch sold her "half-ownership" of a slave boy named Salathiel to Silvanus Hatch in 1760. James Dalton paid Ezekiel Lewis Jr. $40 plus a slave named Prince in 1750, for Lewis's slave named Pompey. Dr. Joseph Warren purchased a slave from Joshua Green in 1770, paying £30 and promising £10 worth of "potters ware" within three months if the slave proved satisfactory.
Disputes and problems occasionally arose regarding the sale and ownership of slaves. Anna Bill gave written testimony in 1761 concerning the sale of two slaves by Capt. John Sale to Nathaniel Brown. Capt. Sale was sued the following year for illegally selling free African Americans as slaves to John Oliver (Desrochers, 636), so there may have been some question as to his ownership of these two. In 1740, Mary Mountire testified as to her sole ownership of two slaves, Kent and Sambo, so that they would not be sold as part of her deceased husband's estate. A buyer could "try out" a slave with an eye to later purchase; Samuel Bowman wrote to Samuel P. Savage in 1752 to explain why he could not keep the slave Pompe, whose behavior made Bowman's wife uneasy.
- Bill of sale from Andrew Boyd to John Chandler for Dinah (a slave), 20 February 1769
- Bill of sale from Malachy Salter, Jr. to James Dalton for a slave, 14 November 1749
- Bill of sale from John Fellows to Theodore Sedgwick for Ton (a slave), 1 July 1777
- Bill of sale from Isaac Powers to John Hancock for Jack (a slave), 22 April 1728
- Bill of sale from Nathan Brown to Elizabeth Cabot for the sale of Phillis (a slave), 26 August 1768
- Deed signed by William Waitt to James Dalton acknowledging the sale of Peter (a slave), 29 July 1747
- Bill of sale from William Richardson to James Dolbeare for Loran (a slave), 9 March 1732
- Bill of sale from Patience Hatch to Silvanus Hatch for Salathiel (a slave), 8 February 1760
- Receipt from Ezekiel Lewis Jr. to James Dalton for exchange of Prince (a slave) for Pompey (a slave), 25 April 1750
- Agreement of Joseph Warren with Joshua Green regarding payment for a slave, 28 June 1770
- Testimony of Anna Bill (manuscript copy) about the sale of two slaves, October 1761
- Deposition of Mary Mountire about the ownership of Kent and Sambo (two slaves), 16 April 1740
- Letter from Samuel Bowman to [Samuel P. Savage?], 14 October 1752