
That's your standard European cabinet hinge, which is in widespread usage throughout the world. It's a great little piece of hardware, easy to install and adjustable so you can get that door to hang and open/close just right. They cost an absurd $13 each at Home Depot, but you can get them at your local hardware store for a few bucks.
I, however, get them at the bargain price of $0, from a different source: The streets of Manhattan. People here throw out cabinetry all the time, particularly Ikea stuff, with the hinges intact. (Ikea uses Hettich hinges, good-quality German-made stuff.) Every time I pass an abandoned cabinet on the sidewalk I note the location, and I'm back there 30 minutes later with my screw gun, shamelessly stripping it of hinges like some kind of homeless carpenter. Most of them open 110 degrees, but you've really hit the jackpot when you find the bulky ones that open 165 degrees, because they're "zero protrusion," meaning you can install them on cabinets with a pull-out drawer or shelf on slides and they won't bump into the door edge.
In any case, there have been plenty of times when I've returned to a discarded cabinetry site too late; I round the corner and get that sinking feeling when I see the cabinet with the doors already off, empty gaping cup holes where the hinges used to be.
It's for that reason I wish I had one of these Screwpop tools. It's just a simple keychain/bottle opener, but it's also got a reversible Phillips/Flathead screwdriver, and even a 1/4" hex driver.

Would I really take the time to manually unscrew a cabinet hinge on the sidewalk? Heck yeah, particularly for one of those 165-degree jammies. I've currently got around $60 worth of free hinges (see below) and I've already incorporated $20 worth into projects. I'm not Donald Trump's son and I ain't proud; so if it's free, it's me.

Comments
for whatever its worth - and as evidenced by your sinking feeling - your not alone. back when i lived in SF, my design partner and i used to make a point of scouring the city clean right at the end / beginning of every month - the prime time for people who are shifting homes to get rid of old versions of literally everything. now my favorite perk of the week is a stop off at the recycling center in town; not only can i get rid of this weeks empty beer can collection, but theres an "eCycle" drop off for anything that takes power. so long as youve got a good eye and quick mitts, you can come away with almost literally gold. more working stereo heads (tubes as well!), amps, speakers, imacs, emacs, laptops, tv's, lcd projectors and who knows what else, all there for the some-what-legal picking.
so far the only thing weve paid for in our 5.1 lcd projected movie theatre room is speaker cable and a griffin firewave.
I'm so glad I'm not the only one who does this. I carry around a screw driver for hardware and wire cutters to get power cords.