Verses with the word seller in the Old Testament (3 verses):

Isaiah 24:2
And it shall be, as with the people, so with the priest; as with the servant, so with his master; as with the maid, so with her mistress; as with the buyer, so with the seller; as with the lender, so with the borrower; as with the taker of usury, so with the giver of usury to him.

Ezekiel 7:12
The time is come, the day draweth near: let not the buyer rejoice, nor the seller mourn: for wrath is upon all the multitude thereof.

Ezekiel 7:13
For the seller shall not return to that which is sold, although they were yet alive: for the vision is touching the whole multitude thereof, which shall not return; neither shall any strengthen himself in the iniquity of his life.