No-one in the industry calls hinges such. We refer to them as joints and they come in halves. Riveted joints are usually found on the nicer frames. There is a pointy metal pin with a flat head (though sometimes a decorative trim but that is complicating things for no good reason). Pointy end goes through the plastic, through some holes in the joint before being trimmed then tapped with a hammer and doming tool on the inside to "mushroom" the end. Be sure it is actually a pinned joint and not a pretend one with dots stuck on the outside. They are surprisingly common as the look was du-ree-grrr for a few years there.
Price is the same if it is a three pin joint or a two pin joint.
Alternatively you may have a heat sunk joint. These are inserted in the frame by the use of a piece of apparatus that is effectively a heated pair of tongs. The joint melts its way into the frame.
On the temple (arm), if it is not pinned then it most likely part of the wire that runs through the temple. Replacing that is troublesome. We'll have to convert it to a pinned joint and you'll get the arm back around 5mm shorter than before.
It is highly unlikely you'll break both halves of the joint assembly so the price is for one half on one side of the frame. If you do break two, let's be friends and double the price.