There's an old saying, some say it is Norwegian - TANSTAAFL.

There Ain't No Such Thing As A Free Lunch.

Any paid ISP is probably doing the same thing. The best thing to do is install ad blocking software. Won't stop whomever from tracking you interests but at least you won't have to look at the ads.

create text file for your message. zip with password. give your relatives and friends the password by phonecall.

password encrypt with 7zip. and shows how to verify (before you send) that you can open with password.
www.youtube.com/watch?v=osdUqxd1Yrs

there's also gpg to work with your email software. i have not yet tried (shame, shame)

afaik, unencrypted email can be read as "plain text" ("in the clear").
unencrypted webmail can be read.

I have used and loved incredimail free for years, since it hit the internet! great for creative ppl, no boring e-mails

There's free, disposable emails services out there. This will let you receive email from a variety of places in a anonymous way without being tracked. But, you can't send it anonymously. Still, it's a great alternative to give out this email address without free of being tracked. http://mailinator.com/

Here is a link that might be useful: http://mailinator.com/