Email Marketing Software

I work for a legitimate organisation that wants to email approximately 1000 people individually.
I’m looking for some software that will easily send emails individually & reliably without disclosing the other recipients in our mailing list. Also I want to avoid getting marked asa spammer.

Are there any free or low products on the market that anyone can recommend?

can any one please help me how to send a email newsletter for a bulk emails without the use of smtp servers

Can anyone suggest if thereis any free software based on php/mySQL that will allow email marketing campaigns, opt-in and such email. I am looking for a free system that I can host on my server and control it the way I want. I can even use my own POP server or if php gives some such functionality .. I am not sure if there is one such system…