SPEEDLITE 430EX II

I consider the 430EX II to be the core of the Canon flash family.
It’s a reasonably priced, fully functional flash that does everything you need a flash to do. As a first flash purchase, I recommend the 430.
It has the focus-assist beam to help you focus in the dark. It can swivel and bounce. It can be used in manual mode with radio triggers, so it makes a great remote slave either with a third-party radio system or with the built-in Canon wireless system.
And although the 430EX II is somewhat less powerful than the larger flashes, I find its smaller size and lighter weight more comfortable for long hours of on-camera flash photography.
I love the 430, and I have lots of them. If you remain a Canon shooter for long, you may end up with lots of them, too.