It's up to you if you want the hassle of trying to maintain a mailing list yourself. I have to maintain a couple of Satchmo stores myself - and using MailChimp is the easiest option in my opinion.
MailChimp offers all the statistics, the ease of sign up, minimal delivery worries, and works well. Once you switch to your own solution you'll have to spend time watching and maintaining your own servers to ensure that mail gets delivered, and start praying that your mail isn't just being delivered to some Spam folder.
If you aren't selling any products and it's just a news mailing list, then obviously the cheapest solution could be the best. However if you've got an online store and these emails are designed to get people buying from it - allocate something towards the cost of it and don't compare it to the cost of the cheapest Linode.
This is just my opinion, and obviously it doesn't really answer your question for an alternative solution.
