Amazon S3 can be an interestingly safe and cheap way to store your important data. Some of the most important data in the world is saved in... MySQL, and surely mine is quite important, so I needed such a script.
If you have a 500mb database (that's 10 times larger than any small site), with the priciest plan, keeping 6 backups (two months, two weeks, two days) costs $0.42 a month ($0.14GB/month). With 99.999999999% durability and 99.99% availability. Uploads are free, downloads would happen only in case you actually need to retrieve the backup (which hopefully won't be needed, but first GB is free, and over that $0.12/GB).
Even better: you get one free year up to 5GB storage and 15GB download. And, if you don't care about all the durability, later you can get the cheaper plan and spend $0.093GB/month.
The cons: you need to give them your credit card number. If you're like me, Amazon already has it anyway.
Another thing that is real nice: HTTPS connection and GPG encryption through s3cmd. Theorically it's safe enough.
Setup
-----
1. Register for Amazon AWS (yes, it asks for credit card)
2. Install s3cmd (following commands are for debian/ubuntu, but you can find how-to for other Linux distributions on [s3tools.org/repositories](http://s3tools.org/repositories))