Can I use a font to create a pillow/t-shirt/mug/piece of stationery that I sell?
Yes, this is permitted so long as the product you create with the purchased font is an End Product. End Products using purchased font Items must be a unique implementation of the font Item. For example, you may purchase a font and use it to make unique word art, or use a font while creating a flyer for an event.
However, it is not permissible to redistribute the original font files in any way.