The Golfsmith website specializes in golfing equipment and offers a number of putting greens from many manufacturers, such as Hank Haney and StarPro Greens. You can also find a selection of cheap putting greens in many sizes on eBay.com, Aliexpress.com and Amazon.com as of 2015.
In addition to the purchase options of ready-made greens, you can create your own greens inexpensively by arranging extension cords, garden hoses or strings in the shape you desire. This sets up the general perimeter of the putting area. Once the size is decided, you can set up the turf by removing the old sod or grass surfaces to prepare the ground for a new installation.