It is possible to purchase a single wheel instead of a full set.
Make sure that when you are planning to order a single wheel that the diameter, width, offset and bolt pattern match your existing wheels.
Wheel information is almost always present on the rear of the spokes of your current wheels. Diameter and width will be marked plainly, with offset often preceded by an 'ET'. Bolt pattern may usually be found by entering your vehicle year, make, model, and trim in your preferred search engine followed by "PCD" (pitch circle diameter).
Your local dealer can assist with pricing, availability and ordering information.