Learn to play well before thinking of spending on pedals, that way you'll probably know what sounds you need and whether you can get them with the gear you already have.

YouTube videos are good for seeing and hearing what different pedals can do, but you also need to be aware that different guitars, pickups and amps also change the tone, so a pedal bought could sound quite different with your guitar and amp from how it sounded in the video.

I also have a theory that pedals are addictive, as my collection currently stands at 30+, I think (I've stopped counting).