The word(s) "purchased" appears 6 time(s) in 6 verse(s) in Quran in Mohsin Khan translation.

(1) These are they who have purchased error for guidance, so their commerce was profitless. And they were not guided.

(2) Those are they who have purchased error at the price of Guidance, and torment at the price of Forgiveness. So how bold they are (for evil deeds which will push them) to the Fire.

(3) (And remember) when Allah took a covenant from those who were given the Scripture (Jews and Christians) to make it (the news of the coming of Prophet Muhammad صلى الله عليه وسلم and the religious knowledge) known and clear to mankind, and not to hide it, but they threw it away behind their backs, and purchased with it some miserable gain! And indeed worst is that which they bought.

(4) They have purchased with the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) of Allah a little gain, and they hindered men from His Way; evil indeed is that which they used to do.

(5) Verily, Allah has purchased of the believers their lives and their properties for (the price) that theirs shall be the Paradise. They fight in Allah's Cause, so they kill (others) and are killed. It is a promise in truth which is binding on Him in the Taurat (Torah) and the Injeel (Gospel) and the Qur'an. And who is truer to his covenant than Allah? Then rejoice in the bargain which you have concluded. That is the supreme success.

(6) (The believers whose lives Allah has purchased are) those who turn to Allah in repentance (from polytheism and hypocrisy, etc.), who worship (Him), who praise (Him), who fast (or go out in Allah's Cause), who bow down (in prayer), who prostrate themselves (in prayer), who enjoin (on people) Al-Ma'ruf (i.e. Islamic Monotheism and all what Islam has ordained) and forbid (people) from Al-Munkar (i.e. disbelief, polytheism of all kinds and all that Islam has forbidden), and who observe the limits set by Allah (do all that Allah has ordained and abstain from all kinds of sins and evil deeds which Allah has forbidden). And give glad tidings to the believers.