Why expensive? because Bitcoin is the first virtual cypto currency that is very popular among investors. Creating Bitcoin is very difficult require multiple computers with high specifications to create it. Also many countries are now legazing Bitcoin to use it for to improve economy of their countries and that's why Bitcoin so high.
But bitcoin, as many coins, is divided into eighteen decimal places, so the price is not a problem when you use Bitcoin as a payment for something. The price for that service can be flexible and extremety low for example 0.00001 BTC to 0.00005 BTC depending on BTC price.