Can I add advanced features like popups or other promotional things?

Yes - and this is one of my fave features of Squarespace as an all-in-one platform! There are a number of ways to help draw attention to special offers or help encourage purchases. These can range from an announcement bar at the top of your homepage to popups on your shop page with offers - even indicators that people have recently purchased certain items. If you use Squarespace email campaigns, you can also easily link directly to items or shop categories in your newsletters.