Home Depot offers the Palm Beach 1-Light Ceiling Fan Light Kit, model no. 72460R, for $29.97. Choose free in-store pickup to dodge the $5.99 shipping charge. That's $10 off and the lowest total price we could find. This kit attaches to adaptable ceiling fans.
There's a less expensive way, and then there's the way that works for you. The two may not be the same.