The Transportation Act 1717 introduced into the house of commons under the Whig government, legitimised transportation as a direct sentence. Clergyable felons, usually destined for branding on the thumb, and petty larceny convicts, usually destined for public whipping, were directly sentenced to transportation to the American colonies for seven years. A sentence of fourteen years was imposed on prisoners guilty of capital offences pardoned by the king. Returning from the colonies before the stated period was a capital offence.1
The purchase price for convicts was lower than that of indenturing servants or buying slaves. Late in the colonial period, a male slave cost £35-£44 whereas most male convicts sold for less than £13, skilled felons for £15-£25. Also, because they were already outlaws from society’s rules, they could be easily exploited.2
In 1722 Daniel Defoe wrote of Moll Flanders that she, on arriving in a Potomac Port, was sold to work in a tavern but, having money of her own, paid the tavern keeper for her “service” and was immediately released. The real life well-off felons probably managed their own freedom in such a way.
As the eighteenth century went on, more and more convicts attempted to escape their masters, most of them young English men or boys. A number of them attempted to board a ship and return home to Great Britain.
The cost [to the government?] of carrying a person across the Atlantic was about £4.3
When the British government developed the legal and practical structures for transporting convicts to America, it used the existing indentured servant market as a model, so there were many similarities between the two trades. Both set fixed terms for servitude before the future servants left port. Indentured servants generally served for a period of 4 years, while convicts who were sentenced to transportation could receive one of three terms: 7 years, 14 years, or banishment for life (74, 24, and 2 percent of the total convicts shipped, respectively). These terms became the length of their servant contracts in colonial America.
3http://www.earlyamericancrime.com/convict-transportation/business-of-transportation/sale-of-convicts This link no longer works. Is £4 correct? If what the government paid merchants was only part of the cost of transportation and convicts would be sold for between £10 to £25, then wouldn’t the cost be at the price they were sold for plus the £3 to £5 the government paid.