The short answer is that InDesign is a desktop publishing tool and was not meant for HTML emails. You could design it in InDesign (or Photoshop for that matter), save it as a PDF or a jpg and just email that. Or you could use the "Export to HTML" tool (InDesign Help | Export content to HTML).
However, due to the frailties of email clients, it is recommended that you learn some HTML, or get someone who does. This would get the best result.
If you don't know HTML there is no way you will be able to use anything but
the on line providers such as those you mentioned and Constant Contact.
i understand that you have not found a very good solution for this.
we have developed a porduct (plugin to InDesign, calles iBrams ID2eMail) and i think that this will solve you request.
I am Happy to provide you with a free Version if you would give us and the community a feedback if you are happy :-) (also if not.....)
just contact me and i will send you the plugin !!!
all the best
but none of them really let me create something freely
The reason for that is there are 20+ email clients out there with varying levels of HTML support. The email services code to the lowest common denominator—tables and no DIVs and CSS. ID exported HTML doesn't use tables so it isn't really usable for email.