They shall have like portions to eat, beside that which cometh of the sale of his patrimony. The sale of his patrimony - So we find that, though the Levites might have no part of the land by lot, yet they were permitted to make purchases of houses, goods, and cattle, yea, of fields also. See the case of Abiathar, 1 Kings 2:26 (note), and of Jeremiah, Jeremiah 32:7-8 (note).
Related Commentaries of Deuteronomy 18:8
Deuteronomy 18:8
8 They shall have like portions to eat, beside that which cometh of the sale of his patrimony.