You have four good options for purchasing your fence:
Home Improvement Stores
Stores like Home Depot and Lowes have a good selection of inexpensive to moderately priced fences and gates. If they do not have the height or color fence you want in stock, they can get it delivered quickly. They also can either provide or recommend local contractors to install their products.
Lumberyards
Lumberyards usually carry fences, but the selection is variable. Lumberyards are more likely to have a selection of fence components, like fence posts and boards, or rolls of chain link fence and posts. Some lumberyards will also have a good selection of fence kits and pre-fabricated fences.
Fence Specialty Stores
If you live in a metropolitan area, there are likely fence specialty shops in your area. These shops tend to display a good selection of medium to high priced fences and gates.
Online Fence Etailers
There are a number of companies now selling fences and gates online. These companies often have a wide selection, good service, and knowledgeable phone representatives. Fenceonline.com and fencetown.com are two of these door etailers.