One option would be to buy cheap shared hosting plans (I've seen as low as $6/mo) and use them only for email. Not always perfect, and things like SSL might be

One option would be to buy cheap shared hosting plans (I've seen as low as $6/mo) and use them only for email. Not always perfect, and things like SSL might be messier, but cheap and easy and these days you'll get as much if not more storage as Google Apps. One drawback to a shared plan is that you might be on the same IP as some spammer and you might get blacklisted. SPF records are easy to set up and can really help with that. I used to manage an email server and it was not very pleasant for someone who just wanted to hack. :-) If you do end up running your own mail server(s) you'll want to be sure you have good spam/virus filtering or users will start complaining. I had really good luck installing Postini a couple years ago -- reduced spam by nearly 100%.