1. To be available for purchase for a particular amount of money. This computer normally sells for nearly $2,000, but it's on sale for just $1,000 this week. They announced that their new product would sell for £500.

2. To make something available for purchase at a particular price point. In this usage, a noun or pronoun is used between "sell" and "at." They originally wanted to sell the video game console for $500, but when sales struggled to pick up, they reduced it to $350. In order to make a profit, we'll need to sell these for at least $30 apiece.