Perhaps you need to take a step back and ask yourself why you need so many computers. It's like someone asking how to keep all his stuff the same in the 5 cars that he owns.
I would suggest you ask yourself what each machine does that your primary machine doesn't, and just make it do that.
Have you considered a good laptop?
If these are all in your house, you could set up a server and keep all the stuff there. Then you just have one machine with data to back up.
If they are remote machines, consider getting a linux vps and store your remote stuff there. Don't use any free online services like github, dropbox, etc, as they can disappear at the wrong time.
Don't use AWS to store your stuff. at $0.1/month/GB, that's $100/month/TB, or $1200/year/TB. For that money, you can buy around 15 Western Digital 1TB hard drives.
If you run a business and make money off it, use the very best service you can get, but to be honest, it's hard to beat hard drives to move lots of data around. Even the 32GB micro USB drives are the size of a fingernail and you can move a lot of data around...
There's the Cloud, the Private Cloud. Maybe there should be the Personal Cloud...