The sport court surface can even be frozen in the winter for ice skating. Of course, the court surface isn't all you need. Nets, net poles and perhaps even soft netting or a chain link fence around the outside of the court need to be figured into the cost. You can see the ball better. Since tennis tends to be a four to five month sport outdoors, you may want to consider options that can extend your season.
Tennis is a lifelong sport and many people have chosen to enjoy it in their own backyard.
Unless your kids are already hoopin' it up on your combo court.