Amazon SQS Price Drops to $0.01 / 10,000 requests
developer.amazonwebservices.com
developer.amazonwebservices.com
Like most Amazon hosted services, they are providing a service so you don't have to host your own hardware and software. You can run your own queue service using RabbitMQ, JMS, or other distributed work queues.
Each active client that checks for short messages every 10 seconds will cost you about one cent per day if there are no messages.
If there are messages, it will cost you 18 cents per gigabyte. Assuming your messages average 128 bytes, every 500k or so messages will cost you another penny.
Of course, you'll probably need at least a few EC2 instances to move messages around between the queues. Not counting your development time, that would probably end up being the largest expense.
I have an idea for a broadcasting system that could use this and I am now tempted with the price drop.