oh that's you
i would imagine that most hostings will prevent you from doing what you want to do.
it would be rather shady business to let you to send emails as someone else, don't you think?
they give you access to sendmail so that you could create contact forms. it's not ment to be used as newsletter thing or contacting clients
but about godaddy ur right. 15 bucks a month for what they offer is kinda steep
i bought hosting here
some time ago. 3 bucks a month and everything works ok. it's not very fast and you can't expect super fast servers, but it might be enough for you