I have everything set up, including offsite backup services, security and sys admin. I authored ami-b033c2d9 and ami-d6e613bf - 2 free Magento/Ubuntu LTS/Apache/APC/Mail, etc images. Ongoing sysadmin is available at a monthly rate from thereon.
If it expensive? Well, a small AMI instance is approx US$70/month to keep up 24x7, and a medium one about double that ( + plus traffic of coure ). Most shops will run on a small instance, thousands of products may need a medium one - you can always upgrade if/when necessary in about 15 minutes. I also have set up alternatives on VPSes from linode. It just costs more because I can't just switch on a prebuild image and present it to you - it is cheaper to run, but a different offering.