What is the most expensive breed of Chihuahua?

Can you tell me what the most expensive breed of Chihuahua is? I've heard that some Chihuahua breeds can fetch a pretty penny due to their unique coat colors, markings, or even their size. Are there any specific Chihuahua breeds that are known for their high price tags? Or is it more about the individual dog's rarity and pedigree? I'd love to hear your insights on this topic.