A garbage truck is a large commercial vehicle that is used to haul refuse to a landfill or other disposal facility. They are similar in design to many other commercial vehicle, most notably dump trucks, and flatbed trucks.
There are three basic categories of garbage trucks, discounting of course any true specialty versions that may have been produced.
Front loader
These are the big boys of the waste hauling industry. They usually feature a ten wheeled chassis, and the largest ones can haul up to 40,000 lbs of garbage. These are the trucks used exclusively for servicing dumpsters. They each feature a set of mechanical arms up front, that is used to pick up and empty dumpsters into the back of the truck. Mack and Peterbilt produce the majority of these in the US market (with Heil producing most of the bodies that go on the frames). A quick check of the used market finds that a ten year old model will sell for around $18,000, with new ones going as high as $200,000.
Rear loader
These are the most common sort of garbage truck (at least in my area, your area might be different). They are a bit smaller than the front loaders. Theses are the ones used in normal residential trash service. They load in the rear, and may have a small set of arms in back that are used to dump the larger trash containers that many people lease from the refuse service. These trucks are equipped with a large garbage mashing mechanism inside, which allows the truck to carry much more than it would normally be able to (by compressing the load). Most of these vehicles are capable of hauling 20,000 lbs of refuse, although some smaller models from IHC can only haul 11,000 lbs. Ford, Mack, and IHC are the largest US manufacturers of these models (although the Ford ones use Cummins engines). Prices range from $7000 - $12,000 for a used older model, to $100,000 or more for a newer Mack or IHC (the Mack ones tend to be the most expensive).
Side loader
The side loaders are much smaller, and are based off of a light truck chassis (as opposed to the heavy truck chassis used on other models). These trucks tend to be used for specialized situations, and are commonly used by companies that need their own refuse truck, but do not need one of the large ones. These can be had from a variety of manufacturers, as they are simply small trash bodies placed onto the standard small service chassis' available from most truck makers (Ford, Dodge, Isuzu, GMC, etc). Used pricing varies wildly, although new ones seem to be in the $60,000 range.
All prices in this article came from web searching on Jan 30, 2002 and are in US Dollars, prices may have changed by the time you read this node.