Nobody is going to let spam 25,000 emails a day for FREE that I know of.
That's 750,000 emails a month without dropping a penny in the bucket.
Mailchimp lets you send 12,000 a month to 2,000 subscribers for free and you have to pay to send to more.
That's 400 emails a day NOT 25,000 LOL.
If there is someone offering email service that let's you do this, PLEASE let me know.
-JB