How much does it cost to trek K2?

I'm curious to know, what is the financial cost associated with embarking on a trek to K2, the world's second-highest mountain? Are there various expenses that one should consider, such as gear, permits, and travel to the base camp? Is the cost significantly different depending on the season or the route chosen? Additionally, are there any unexpected costs that trekkers often encounter during their journey to the summit of this formidable peak? Understanding the financial commitment upfront can help individuals plan their expedition more effectively.