Alternatives for outbound email service

[richb-RBmg6HWzfGThzJAekONQAQ at public.gmane.org (Rich Braun)]

> I tunnel my mail through a co-located mail server ...

That's one way to get an external routable IP address, but I don't have that
right now.

Acquaintances have told me that Amazon EC2's pricing has dropped considerably,
and a quick check of their site shows that for $54/year one can get a "micro
reserved instance" which is 613MB of RAM plus ten cents/month/GB for storage,
so a 10GB partition (more than needed for a mail relay) would be $12/year. 
That's a price I could live with though the price list is daunting and I
suspect those would not be the only line items on the bill.

So, if I follow John's suggestion and actually purchase a colo mail server,
how do I keep the cost down under, say, $100/year?  (The obvious alternative
is to buy commercial-grade home ISP service, which is unnecessary and frankly
the home email server is a luxury that I don't really need but prefer to keep
for the sake of principle--it's something I've had since the "old days" of the
Internet when all these restrictions and costs didn't exist.)

-rich