As side project at Optimal I needed to have my own Internet accessible instance of Apex up and running. It provided a good opportunity to see what the "Cloud" could provide.
Plan A was to stand up a Amazon Oracle RDS and a EC2 to act as the HTTP listener, t1.micros instances for the technical people out there. I found out that Amazon can provide you a Oracle database and take care of the backups as well starting out at 6 cents per hour. With no Oracle license cost it's an very cost effective way to use one of the best databases platforms available.
I hit few of issues with this that led me to needing a Plan B. Firstly the t1.micro database option did no allow for Apex option of the database to be enabled. I'd have to move to the next level which was over 3 times the cost and provide far more resources than I needed. Secondly Amazon only supported a previous version of Apex. Being a managed database instance I did not have access to SYS so I could not upgrade it myself.
So a plan B was dreamed up. I decided to put Oracle XE database on a EC2. I'd have to manage my own backups but at least I'd have the Apex version I wanted. I found a helpful blog that gave a good guide in the process. They didn't include an Apex upgrade process but Oracle's guide is easy to follow.
So excluding the false start with Plan A, I managed to create a Linux server with Oracle Database and Apex in under a day. Not bad going in my opinion.
You can try the Amazon yourself if you want. Amazon provide a free servers for all.
Have fun in the cloud,