United States
They are called commanders and no there is no cost involved.
The reason you should wait to choose a commander is so you can choose one that will help counter whatever your opponent is doing, but there are plenty of commanders that provide early units and bonuses so choosing one early can be good too. It's a tactical choice that is up to you and there is no "wrong" time to choose a commander.
I believe it's a strategic choice rather than tactical.
On the other hand, if you aren't brand new then it seems you have made a duplicate account (don't people get banned for that?) and your first post is an obviously biased two sentence mini-rant... Honestly, 
Zeh Lothiack
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cblanco ★ 
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VonManteuffel 
