What takes up Storage Space on a phone(Android)?

[Alphonse]

I recently got a samsung galaxy ace about a month ago.

I noticed that the Storage Space MB was at near 116-118
It would always lower and decrease when I would delete something
But now, it's at 124 for some reason, I don't have that many apps, Just facebook, Google Play store and Fruit Ninja(Its a fun game, dont blame me)
And the weird thing is that my MB has been at 116-118 when these were all installed.

It just instantly increased some how.
I have downloaded a GBA app and 2 games, but even after that, I deleted them.
Yet, I still have 124/181MB

My question is:What uses Storage Space and How can I get my Storage Space to lower?
Already have a MicroSD,

And sorry, i got the problem resolved, turns out that updates take space too xD

But anywho, thanks!

[Uncle Albert]

No sure what the problem is, but if you want more space, you can always buy a microSD card.

[Isaiah Hughes]

Apps CACHE is a major one. Also if all of your Facebook contacts are synced. But go on the google play store, and download an app called history eraser. It deletes everything that could be taking up space, like cache, browser history, and etc. Be sure to uncheck the delete call history option if you don't want to loose your call logs