The internet is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think the /22 you got as a LIR was big, but that’s just peanuts to the internet.
Well, actually, it wasn’t in the long run, that’s why we need IPv6. But that is a different story.
The point is, IPv4 (the most common deployed version of the IP protocol) sets its address limits at 2³² addresses. This means you have roughly 4.2 billion IP addresses to work with, except you don’t really, because large sections are not usable: