I want to go to Europe

I really want to visit Europe someday. Maybe I go there next year. I have a friend in Paris. He's a French guy but speaks Japanese fluently. I think I'm very luckey to be his friend because he says I'm always welcomed to stay at his place and he's gonna me around the city. I don't wanna visit only Paris but also visit other countries in Europe such as Italy, German, and Spain. The only problem is that I don't have money to get the airplane tickets. Why are planes so expensive? They should lower down the price immediately.