When I signed up to be a Stampin' Up! Demonstrator close to 5 years ago, the pastels were one of the things in my starter kit. I love my pastels, but I go in spurts of using them. But they are really a great value because you get all 48 regular SU! colours, and with a set of blender pens, you can colour in your projects to match your paper, and accessories, even if you don't have all the markers or ink colours. Pastels can also be used dry, and the set comes with little applicators, but you can also use regular Q-tips.
But, another fun thing to do with your pastels is a technique called "Poppin' Pastels." You just stamp your image in Versamark and then with a sponge or other applicator and watch the image appear before your eyes!! The images on the red paper below have been stamped in Versamark as well, and they just give a watermark effect.... Versamark is a pretty cool product, too!
Here is a sample of this... one of my card club projects from last week.