Yes, you can use Unsplash photos as part of a product you sell. For example, using an Unsplash photo on a website that sells a product or service is fine.
However you cannot sell an Unsplash photographer’s photo without first updating, modifying, or otherwise incorporating new creative elements into the photos (i.e., selling unaltered copies of the photos). This includes selling the photos as prints or printed on physical goods.
Our Made with Unsplash collection has many examples of products created with Unsplash photos that showcase how photos can be used creatively.