Relax, Kakao Games is not robbing you. It's just because it's easier for players to make in-game currency in the game today compared to a year ago when Black Desert was just released. When the general players has a large amount of fortune, the price for the supplies has to be increased to make sure the economy is balanced. Therefore, Kakao Games decided to increase the price for cash shop items listed on the auction house (in-game marketplace) by 50%. The price increase will happen on July 19th, so if you can plan and prepare now.
In case you don't know, players can sell cash shop items in the in-game marketplace for silver, the in-game money of Black Desert. It's been pretty easy for a player to purchase some cash shop costumes from the marketplace when he's pretty established in the game. It's a fair move to increase the price to keep the economy running healthily but it's another thing that whether the 50% increase rate can make the majority happy.