Without wading into the kerfluffle around SendGrid that’s going on this week, here’s a partial list of commercial email service providers that compete with SendGrid. I am specifically focusing on products that provide pay-as-you-go pricing since that’s what we need.
Amazon Simple Email Service lets you send 2,000 messages for free each day if you send mail from an Amazon EC2 instance. Otherwise, pricing is $0.10 per thousand or $0.0001 per message. This makes Amazon one of the most aggressively-priced commercial email service providers around. I found Amazon SES to be challenging to configure and lacking some of the dedicated providers’ features such as a deliverability dashboard. We stopped using SES last year for this reason, but as our volume increases we will consider going back to them.
Postmark charges $1.50 per thousand emails (so, $0.0015 per message). They have a free trial that lets you send 1,000 emails for free. They also provide discounts if you’re sending 500,000 messages or more each month (we’ll get there someday). It looks like they have you pay up front and draw down your account balance like MailChimp does, but they’re a true pay-as-you-go service. Thanks to @torrez for the recommendation.
Mailgun, owned by Rackspace, is not a purely pay-as-you-go service since they have monthly minimums. Their standard account is $1.00 per thousand (so, $0.001 per message) with a $19/month minimum. So this seems like it would would be a good choice if you were planning to send in the ballpark of 15,000 messages or more each month. (They have higher volume plans that reduce the cost per message.) Thanks to @jetsetter for the recommendation.
Vertical Response says they charge $0.01 per email, but it looks like that pricing is variable depending on how much you use (we do email blasts to about 6,000 users which they say would cost $72.00, or $0.012 per email).
Constant Contact does not appear to provide pay-as-you-go pricing. They charge $50 a month for up to 5,000 emails, or $0.01 per email. (They have more expensive monthly plans that bring down the price per message.) Because they don’t offer pay-as-you-go pricing, you’ll almost certainly wind up paying for more capacity than you need.
MailChimp requires that you purchase credits ahead of time to get pay-as-you-go pricing. A $100 prepayment gets you 5,000 credits (that’s $0.02 per email, which makes them one of the more expensive providers).
Campaign Monitor charges $5 per “campaign” plus $0.01 per recipient, but unlike a lot of providers they don’t place restrictions on transactional versus non-transactional (marketing) mails. A transactional email is one that’s sent as a result of a user action (like registering for your site, or in the case of CodeLesson, enrolling in a course). When you’re choosing a provider it’s best to carefully review their terms of service to ensure that what you need is in alignment with what the provider’s terms.
I’m sure there are more providers that provide pay-as-you-go pricing, and I realize that price-per-message is not the only important metric. If you’re using a provider you like, please recommend them in the comments.