Making external calls

Dear Asterisk community. I am new to the whole telephony thing and discovered the existence of Asterisk which I am hoping is the software I need. I have a question which I cannot seem to find an answer for.

Is it possible to make automated calls to any mobile around with world with this software?

If it is possible, how much does it cost and is it possible to make simultaneous calls?

If yes, how many calls can be made as any given time?

I hope I have come to the right place, if not, please point me to the right place where I can find the answer to these questions.