Are horses rare in Minecraft?

Hi, (i'm a girl) and i play Minecraft PC Survival most of the time. I was on a search for wolves, jungles and cocoa beans (which, btw, I DIDN't find yet)
Instead i came across these horses, which was kind of unexpected. People say that they are rare. Unfortunately, I don't have any saddles, but I really want want want to tame them! I'm actually really far from my spawn point, so I'm slightly limited in resources. I read that horses can despawn, so I'm even more anxious to tame and ride them.
Are horses rare? Right now in a plain, I found a cluster of over 15 horses in an area. I really wish i had a lead so i could lead them home to my spawn point. (My spawn point is where my house and chests are located)

Um… So yea my questions basically are, are horses rare-and do they despawn? How can i find a dungeon real quick?

Horses usually spawn in the Plains.
Search in the diamond levels, your more likely to find a dungeon there.

Horses aren't rare and they do not despawn and to find a dugeon, you have to mine and go underground. You will fall into a dark hole and that's the dungeon.

Semi rare but you should have no trouble finding others