If you are looking for a simple and free backup solution then I would suggest you to try Toucan. Toucan is a portable freeware application which can be used to synchronise, backup and encrypt your data. As this is a portable application you can carry it in your thumb drive and use it anywhere.
Toucan is really very simple to use. You can take backup of your data with just few clicks. Toucan supports ZIP or 7-ZIP compression formats. You can even give a password to protect your data. It supports 4 types of synchronization modes – copy, update, mirror and equalise. You can also encrypt your data using Rijndael or Blowfish algorithms. Toucan has got a command line support which allow you to create a batch file for repeated jobs.