You can buy GE downdraft gas ranges from a number of online retailers and, depending on your location, some local stores. Because the vast majority of GE brand appliances are sold through retailers, GE's website offers a search tool to help shoppers find local dealers.
On GE's homepage, locate the Where to Buy link in the top right corner of the page (as of February 2015). A Where to Buy button is also included on each product page. Unfortunately, GE's dealer locator tool does not specifically say whether the local retailers carry the specific item you are looking for, so you may want to use the provided phone number to call and ask. The list of local GE dealers does distinguish between retailers, showcase retailers and preferred contract distributors, with showcase retailers carrying a larger selection and showroom displays of GE appliances. (Preferred contract providers serve builders and contractors.)
GE's search tool also lists national GE dealers, such as Sears, The Home Depot and Lowe's. These stores' websites have pricing information on a wide range of GE appliances, including a few downdraft gas ranges, that can be ordered online. GE also has an online Warehouse Sale section on its website, with free shipping on limited inventory based on your location.