There is no rule in the choice of container for floral arrangement. If you cannot find any good vase that fits with the floral design you have in your mind, you can use any kind of glass, cup, dish or utensil in the kitchen. The photo in this page shows arrangement made in a mug cup and a wine glass as well.
If the arrangement is so tiny like this, mug cup, tea cup or coffee cupt are quite useful as a substitute vase. Even a wine glass can be a simple vase for simple arrangement as the photo shows. California Flower Art Academy offers a Wide Range of Programs for teaching various floral designs from easy to difficult ones, simple to high end ones. You can make a right choice of a program or course from the above Program List depending on your taste, budget and purpose of learning flower arrangement.
If you are interested in learning easy floral arrangement, California Flower Arrangement can help. For more information, please do not hesitate to contact firstname.lastname@example.org