Different models of 4x4 quads are designed for sometimes vastly different purposes, so before choosing a quad for you, you will need to determine how you are most likely to use the vehicle. A hunter, for example, will want to look into 4x4 quads with racks for storage, while a quad racer will simply want a lightweight and maneuverable quad that will go fast and steer nimbly. A quad for work purposes, perhaps used by a wilderness guide or even a logger, will need to be built for towing, hauling, and handling treacherous terrain.
Once you have determined what type of 4x4 quads you are considering, draw up a budget for purchasing the quad. The price of a quad can vary significantly according to the size, design, additional features, and manufacturer, so you will need to determine your price range before shopping. Your price range may dictate whether you need to look for used 4x4 quads, which opens up another level of research that you will need to be aware of to avoid purchasing a quad that is not in ideal shape. In either case, the engine size will be one of the bigger determining factors of price, so be sure to decide how powerful of a quad you will need.
Consider what extra features are included with the 4x4 quads you are considering. Some larger quads for hunting or work purposes often include racks and winches, which can increase the value of a particular quad. If the quad does not have these features, you may need to purchase them after the purchase of the vehicle, which means the overall cost of the vehicle will rise. If the 4x4 quads you are considering do have these features, be sure to test them out to make sure they work properly. Inspect winch cables for damage; if the cable is damaged, the quad is probably still worth purchasing, as the cable can be replaced for a fairly low price.
If you are purchasing a new quad, be sure to ask about any warranties that come with the purchase. Used quads will not generally come with any warranties, but if you are buying from a dealer, it never hurts to ask about warranties and return policies. If you are purchasing used, be sure to ask the owner about any past repairs or parts replacements, as well as any ongoing problems the quad may have that you will eventually need to address.