The hand that sells the items is connected to a person who is known as the seller or the vendor.
This word uses the kun'yomi readings for both kanji, but you know them both now, so you should be able to read this too! One hint that this is a kun'yomi reading word is the hiragana in the center. It's like two separate words combined together, and when a word is a single kanji / a single kanji with hiragana attached it is usually kun'yomi. This is like two of those, combined.
I was cheated by that vendor.
This's the hottest seller's market ever.
The guy selling that house told me he’s selling it because his neighbor is a real jerk.