New to Samsung Epic

[nyclegend20]

I finally jumped the boat fro the Touch Pro 2.
Sprint finally got me to change my legacy plan.
Paying almost double a month for less minutes and right to use a "new generation smartphone"

I have cusotmized my tp2 i unlocked it installed different roms etc.

I wanted to know what rooting does for the Epic?
Are there roms to install or does everyone do own customizations?

How can you install roms?

I am just so confused with android.

Are all apps in the android store free?

Is their like a jailbreak to get apps for free like on the iphone