If that's all you want, go to nearlyfreespeech, set up your domain there, and tell it to forward emails to your gmail account. Your gmail account then can send email under that name. I did it for quite a while.
It works, but Outlook (or at least some versions) will always show your emails as being from something like "address-you-forward-to@gmail.com (via you@your-real-domain.com)" which is annoying.
