Also see definition of "Purchase" in Word Study
Study Dictionary
Purchase
PURCHASE [ISBE]
PURCHASE - pur'-chats: In modern English, "to acquire by payment," in Elizabethan English, "to acquire" by any means. In the Old Testament, the King James Version has used "purchase" to represent qanah, and its derivatives (verb and noun), except in Lev 25:33, where the word is ga'al (the Revised Version (British and American) "redeem"). In the New Testament the noun does not occur and the verb is used for ktaomai, in Acts 1:18; 8:20, and peripoieo, in Acts 20:28; 1 Tim 3:13. But none of these words connotes the payment of a price, so that the Revised Version (British and American) has kept the word only in Acts 20:28 (margin "acquired"), changing it into "obtain" in Acts 1:18; 8:20, and "gain" in 1 Tim 3:13. In the Old Testament, the Revised Version margin has "gotten" in Ex 15:16 and the American Standard Revised Version has (very properly) introduced the same word into the text of Ps 74:2; 78:54.Burton Scott Easton
Also see definition of "Purchase" in Word Study