You should buy games instead of pirating them because it is the right thing to do. The people who created the games puta lot of work into the process and they deserve to be paid for their work. Also, if you are not motivated by doing the right thing, there are ways you can get caught if you pirate games online. There are some significant fines based on the amount of content that you steal.
You may find that it is not worth the risk to pirate games and instead just pay the upfront cost so you can sleep better at night without worrying about you was hurt by your piracy and whether you will get caught.