OK, you ask for Best Backup Software, then you say you want it free.

Acronis would probably be the best.  But it's not free.

http://www.acronis.com/en-us/personal/pc-backup 

Best free?  Maybe Easeus To Do?

http://www.todo-backup.com/products/home/free-backup-software.htm 

Easus is a good one but if you want one that does it best without jerking you around open your purse and buy Acronis. Spending some now will prevent future headaches. Right now if I could...I'd spend the bucks and do it up right the first time because later on you might regret it. Just saying!

You set it up once...and forget.  Can't get much easier...

What he said. 

It is when you switch machines often. I'll look into getting Acronis when I have some income. Thanks guys.

If they're networked you can backup across the network.

If they have the same folder tree [OS] you can use the same setup/config for all of them.

If not you can copy the config to other machines and edit as needed.

Ultimately it is one config per machine....and the same applies to ANY backup software...

http://www.techradar.com/us/news/software/applications/best-free-backup-software-11-programs-we-recommend-1137924

You're welcome 

Thanks guys.

I think it also depends on how much data you're looking to keep backed up.  If you're talking limited data, like 20-30gb, I would probably look into an online service as long as the person has a high speed connection.  My box.com account came with 50GB which is nice for targeted data.

If there's ANY personal or financial data involved, DO NOT use a cloud backup.

While tempting because of your personal circumstances at the moment, any breach of that service will put whatever in the hands of bad people. That said, CloudBacko states it uses military grade 256 bit encryption ("truly randomized").

I would only point out that frequently, buisnesses offer "unlimited" when in fact, it means "unlimited so that you put all your stuff here, but we have plans to change that in the future." A "bait and switch", if you get my drift.