Hard drive backup freeware is an inexpensive way to protect your data. I need full backup of my hard drive and want to know the best freeware for this task.
Please suggest the best one from your own experience.

It sounds as though you are looking for a free way to back it up rather than an inexpensive way
You can always use the course of action provided by your OS. It is free, already installed, provides directions, and least likely to cause you problems.

Here is an Open Source tool: PartImage

As for backing up with a non-free option, I like Ghost. I really hate Norton products for the most part, but they have just been working on this little goodie for so long one can't deny it.

online you can try MOZY
google that word and sign up for free

I would recommend SelfImage and 'EASEUS Disk Copy' for this purpose. Free, friendly and powerful enough for backup entire hard drives or partitions.

Hard drive backup freeware is an inexpensive way to protect your data. If your data is important to you but you’re on a budget, then you might want to consider using one of the many free windows backup programs available to you. I've created a short list of reliable freeware backup software to aid you in your search. This is all well-behaved freeware. They don't contain spyware, they won't nag you to buy something else, and if you don't like it, they're easy to uninstall.