Dumpsters are measured in tons and yards.  Disposal companies charge a flat fee to haul it, as long as it doesn't go overwieght.  You're charged extra if it's too heavy, but as a guy once told my brother, "They don't respect you unless you overload it."
    He lined the edges of his fifteen yard dumpster with junked doors, like cucumbers around a small salad bowl.

    This guy wasn't a contractor- professionals know that disposal can wreck your margins, especially on small jobs where the cost of hauling might equal time and materials.
    There are opportunites for ferreting away small amounts of extra trash on the site.  It can be set out on the curb along with household garbage, as long as it's in white Hefty kitchen bags.  If there's any excavation going on, refuse can be buried, but countertops and refridgerators are bouyant in soil, and the old kitchen will eventually start poking through the backyard turf.  Refuse can sometimes be buried in concrete, too, but murder will out when the foundation gives way, revealing errant plywood and paint rags.  In general, any large amount of construction debris needs to be disposed of in a dumpster.
    Because of this, contrators with heavy or hazardous waste will keep an eye out for new construction sites in the area, looking for an unsupervised dumpster to abuse.  It's fun, a reverse theft that shifts the disposal burden directly onto the competition.  In New York City, where rates are high, an open dumpster needs to be filled the same day it's set out.  Otherwise, someone else will top it off overnight, with wet cement or sprung razor wire.  
    Slipping someone else your trash can get you rebar'd in the big city, if you're caught in the act, but pirating dumpsters can be dangerous in small towns, too, especially if you're disposing of anything distinctive like mixed paint.  Contractors will go out of their way to match colors, and homeowners can get in real trouble if they try it.  A good contractor packs a dumpster like a chinese puzzle box, maximizing the space and eliminating any gaps.  Other people's garbage sticks out, and builders will open bags looking for utility bills or junk mail.  The most restrained response is to return all the garbage to the address listed through the mail slot.
    1If you're doing a lot of excavation or demolishing masonry, a "dirt dumpster" is a good idea.  It's a regular box, but it can contracturally accept a lot more weight, usually about ten times more than a standard can of the same dimensions.  However, it can only be filled with dirt, masonry, and sometimes roofing materials.  If there's a stray 2X4 or a soda bottle at the bottom, they can treat the entire load as standard refuse, putting you fifteen or twenty tons overweight.  It's in these situations that you need to be sure you've got a secure worksite.  
    Hazardous materials can't be thrown into regular dumpsters, either.  If you don't want to pay for hazmat disposal, you've got to conceal your poison; mix gasoline with broken plaster, or pour off thinner into old coffee cups.  We haven't had a toilet on the site recently, which is a code violation.  Instead, I've been saving cups from Dunkin' Doughnuts.  For every 16 oz. I drink, I return about 13 oz. to the cup.  This works well, even with the transparent iced coffee cups, as long as you leave a little in the bottom to give it the right color.  Gaitoraide bottles work, too.    A few weeks ago, a guy pulled up in a van at our site and asked if he could go into our dumpster for salvage metal.  I said that he could, and left for lunch.  It didn't occur to me to warn him.