As long as they are labeled for commercial use, you can use stock photos in multiple designs and projects with a for-profit purpose, including websites, marketing and advertising, branding, and more. If the photos are labeled as Editorial, you can only use them for this end (never commercially).
What Sells Best On Shutterstock?
Some types of photos that sell best are Portrait Photography, Food Photography, Landscapes (usually with people) and fine art photography (artsy).