I recommend looking at Campaigner:
http://www.campaigner.com/. I no longer use it or any email marketing tool, but it was the best tool I evaluated and it was the most affordable. I believe they still offer a free evaluation period, so no harm in checking it out.
For $25 a month, you get a decent allowance for total recipients (one we never came close to reaching). You can use their templates or upload your own html campaign, and either option is pretty straight forward. I had originally tried to manage the email campaigns without a tool, but keeping up with mailing list removal requests was tedious. Your email recipients can remove themselves from your list, which in itself is easily worth the $25 a month. I believe they also have a “pay as you go” plan, which might be a better choice if you don’t plan on sending out a message each month.
For another $5 a month, you can allow users to add themselves to your mailing list. You do this via a “join our mailing list” link on your website. From their dashboard, you can see who opened, deleted, or forwarded the email, as well as see which links were clicked on and who asked to be removed from the list. Overall a pretty nice tool, easy to use, and professional looking results.
We sent emails to customers only (never bought a list), and got their okay by offering a drawing for a free dinner. We stated that all winners would be notified via email and that by playing they would be added to a mailing list they could remove themselves from at anytime. We got a mixed response to our emails. Some customers thanked us for the email updates, others griped out being “spammed”, and the rest remain a mystery. I didn’t feel there was a big enough return on the time spent on these campaigns, and had to give it up for other priorities.
Our emails included things like updates on menu additions, things we were doing in the community or recognition we had received, upcoming events, etc. One thing we never did was offer a coupon, which I imagine would be a much bigger hit, especially for those who griped about receiving the message. If and when I take this effort up again, I would use Campaigner and most likely include a special or coupon to create a better sense of value to the customer.
Good luck!