Dont ignore if this sounds like a duplicate. I went through similar questions here but couldnt resolve my doubts.

Im developing a site in my localhost. Its coded in PHP. I need to send mail to my site's customers from my PHP script. I know we can use gmail smtp server for this. But due to the limit on the mail/day set by google, i prefer not to use them.

But my doubts are: 

1. Can i do it without gmail's smtp server or anyone else's smtp server?
2. What all components would i need to send mails from my localhost as well as from my online webserver?
3. Does all the webservers come pre-configured to enable us to send mail from site?
4. What is sendMail, phpMailer, pearMail etc.? I've been advised to use them. But what are they?

Thanks a lot!

EDIT: Im using wamp2.2 in my localhost.