Yes...in the landscaping department of most big-box hardware stores such as Lowes or Home Depot. But they come attached to the rest of the plant!

Sweet potato vines are used as a landscaping plant all over the Houston/Gulf Coast area because they are one of the few plants which can handle our summer weather. They form the groundcover of my front flower beds and grow really fast so I have an almost endless supply. When conditions are right I also end up with sweet potato tubers just in time for Thanksgiving.
-Blast