We sold the remaining goods at half price.
You can return any unsold stock, so would you let us sell our products here?
Before we leave the store tonight, let’s go ahead and count the remaining stock.
The remainder products are the things that haven't been sold. It's the unsold merchandise. It's the remaining stock.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Note that ひん changes to ぴん.