Dear

Having had the pleasure of mailing you (name of magazine)
every month for the past three years, we were wondering if
perhaps you haven’t realized that your subscription ran
out in (month)

We mailed you our (month) issue and have not yet
removed your name from our subscriber’s list inasmuch as
we felt that you may be unaware that it is time for your
renewal.

We have enclosed our renewal subscription card for you
which provides for 12 issues of (name of magazine)
at the low price of $ per issue, or $ less
than the newsstand price. As you can see, this represents
a substantial savings.

We are looking forward to hearing from you soon.