You don't need to buy any backup software. The bottom line is there are now only three hard disk manufacturers. In practice you will have at least one internal or external hard disk from either Seagate or Western Digital. Both have Acronis True Image as a free download but you must have at least one drive from that manufacturer on the system for the software to run. The only negative is that you can't back up just particular files or folders with the OEM versions. But you can just use some form of Copy and Paste for that. At work we use RichCopy, which is free from Microsoft. It lets you set up multiple copy streams simultaneously and if a file is locked, etc., it just ignores that file and checks again later, whereas Window's built-in copy-and-paste routinely stops if a file can't be copied. In fact, we run two instances of RichCopy simultaneously on the same server, one backing up files from that server and the second instance backing up files from the other server, both onto a Dell hard-disk cartridge on the main server.
Over the past several months I've had two Win 8 crashes where I had Acronis backups. In one case I was able to restore the entire disk from the backup and in the other I couldn't although there was nothing wrong with the backup. I don't know the reason for the difference. Both were to SSD's.
One thing nice about True Image is that although the backups can be highly compressed, files and folders can be accessed like any other files.
A few months ago I bought the latest version of PKZip from PKWare. If I just have to back up certain folders I use that until I do a full disk backup. If you download the trial version and then wait a few days you'll get an email offering a 50% discount, which comes to $15. I haven't tried any of the freeware Zip programs but they may work for backups too. I already had an older version of PKZip but wanted to make a single Zip file with about 145GB of data and I didn't want to risk waiting several hours for the data to be Zipped and then possibly be told either the file could not be saved or the Zip was corrupted.