I'm no longer tracking all of these things separately, so it would take some digging to calculate the total Inquisition budget and the like.
One easy example is Kings Landing, where the Inquisition currently costs us 3,000 IM a month, which will double to 6,000 IM once we are firmly entrenched by cannibalizing Varys former network.
What you get for that is around 1,000 full time Inquisition spooks (numbers will build up over the coming months, until then we basically spend what we save on wages on more informants) and a wide net of well paid informants. This isn't limited to the city itself, but also extends to the surrounding densely populated farmlands around the Blackwater and all those minor houses and holdings within a days march of KL. So when Farmer McPeasant sees a procession of Lannister Golden Shields coming for the capitol, he will go to that nice fellow in the local tavern, tell him everything he saw and get a few shiny coins for his effort.
That fellow is a Handler, who keeps many such informants and will likely get more then one report on the matter. So he writes everything down and sends a Raven to KL with the intel. There, a perfectly normal looking house receives the letter and a clerk starts making a full report out of all the sightings. That report goes to Chatayas, where the whispering brazier is used to forward it to SD.
In SD, they now cross reference this with other Golden Shields files and get some urgent divinations from the House of Mirrors, maybe throwing in a Scry for good measure to get a good look at those people.
By the time the Lannisters walk into KL, Viserys has a report on his desk about their number, equipment, likely purpose and the personal files of everyone notable enough to warrant one.
