If you debase something, you make it worth less, or you make people respect it less. The old, strict use was about money: a ruler debased the coins by mixing in cheap metal, so each coin bought less. People still say this about a currency. Then the word stretched. You can debase an office by acting badly in it, debase a language by being careless with it, or debase yourself by doing something you know is low. It is a formal, rather severe word. You would not use it for a small everyday drop in price.