How are hyperlanes operated or controlled in Star Wars?

In Star Wars, hyperlanes are:

A hyperlane, also known as a hyperroute, hyperway, hyperspace route, hyperspace lane, spacelane, star-route, or trade route, was an area of space that had been deemed safe for hyperspace travel. The largest were known as super-hyperroutes.

And the wikia's more extensive answer is:

Hyperlanes were routes through space in which a spaceship could safely travel without colliding with a body in space, or some other phenomenon such as a black hole. There were about eight major routes in the galaxy, with hundreds of secondary routes and thousands of minor ones. Scouting new hyperspace routes was an incredibly dangerous task for an explorer.

In many parts of the galaxy hyperlanes also involved periodic re-entry into realspace. This was so as to manually maneuver the ship towards the next hyper-point. It was in these spots that pirate raids were common. The Galactic Empire and other governments often sought to lessen this threat by constructing deep-space platforms at hyper-points. Mine fields and probe droids were also deployed.

But how do they actually work? Are they merely coordinates? Is there some reason why in vastness of space there are so few of them? "Hundreds" and "Thousands" is actually a pittance compared to the incredible size of the Galaxy. Why are they so rare and valuable? From the description of The Great Hyperspace War:

During the height of the Sith Empire, two Republic hyperspace explorers stumbled upon the Sith mausoleum planet of Korriban by chance. The siblings, Gav and Jori Daragon, hoped to discover a lucrative new hyperspace route that would help them pay off their enormous debts.

How would one "sell" a new hyperlane? It seems like once one other person has the coordinates, it diminishes in value exponentially as the coordinates are "sold" again. Once someone knows the coordinates are safe, they can share or sell those coordinates. In fact, it is baffling to why droids couldn't be used to the same thing the Daragons are doing to unlock virtually every possible route in a region in a relatively short period of time. Especially considered the rather lowly peg on the totem pole droids occupy in Star Wars culture. Both sentient and expendable? Seems like a good explorer to me.

I can't remember a single point in movies or books where traveling by hyperspace is controlled in any way. We don't see ships being stopped for tolls, we don't see anyone buying a new hyperlane or even really worrying about them - they just punch in some numbers and...

Answer

The concept of hyperlanes was something that was added to the Star Wars mythos shortly before the New Jedi Order series was launched, primarily to enable a clearly-recognisable invasion route for the Yuuzhan Vong to follow. If you read those books - in which case, you have my sympathy - you'll note that the Vong primarily followed pre-existing hyperspace routes in their invasion.

The concept isn't a completely stupid one; if hyperspace involves finding safe routes where one doesn't "fly right through a star or bounce too close to a supernova" then it makes perfect sense that well-travelled, well-mapped routes which are known to be safe would be at a premium. It also makes sense that discovering a new route would be potentially profitable; as you said, the discoverer should be able to sell the lane's coordinates for profit. There is only one case, to my knowledge, of this occurring in the EU; in Destiny's Way, the Imperial Remnant trades its knowledge of Deep Core hyperspace routes to the Galactic Federation of Free Alliances in exchange for intelligence on the Yuuzhan Vong, specifically their military capabilities. But even one occurrence should serve to prove that such routes are valuable commodities.

Timothy Zahn's Spectre of the Past also mentions the Corporate Sector spending a lot of credits on 'fly-by' exploration; that is, jumping from hyperspace, scanning to make sure there's nothing dangerous, then jumping out again. It's highly-likely such exploration was automated, and given the Corporate Sector's proximity to the Unknown Regions, one would suppose that the discovery of safe hyperspace routes was potentially profitable to the Corporates, both for the monopoly on any systems they found and through sale of the coordinates themselves.

It also makes perfect sense that a smuggler like Han Solo might stray from the beaten path, so to speak, and have knowledge of 'back-lanes' that enable one to travel through hyperspace more quickly, or possibly simply to avoid patrols; Jedi Search posits that Han Solo does indeed know such routes to and from Kessel, which explains the line from A New Hope where he says; "She's the only ship to make the Kessel Run in less than twelve parsecs."

Obviously, once a ship is in hyperspace it isn't coming out until it is forced to or wants to, and the idea of setting up interdictors or forcing ships to pay tolls to use hyperlanes is unworkable. What is workable, however, is parking an interdictor in a popular hyperlane and capturing vessels fleeing a newly-captured planet along that route, as the Yuuzhan Vong did in Destiny's Way, or mining a route to create a trap for a military force, as the GFFA did to the Yuuzhan Vong in that same novel. So knowledge of hyperlanes is useful not just economically, but militarily.

There is also some mention of the Rakata, who had hyper-gates rather than ships capable of entering hyperspace on their own, only being able to travel through certain safe routes, though this obviously pre-dates even the Old Republic, let alone modern hyperspace technology.