Win8. A warning keeps saying that I have low disk space. Free or paid programs should I take?

Maybe u have downloaded too much movies and other programs. Just check the files to delete. I recommend you to download Colorful Disk Clean. It is a new product which is specially designed for the Windows8. This program is quite cheap and simple to use.

http:(IGNORE)//apps.microsoft.com/windows/en-us/app/colorful-disk-clean/2972d7f6-b902-44d1-999a-8f4e49db8923

Use the disk cleanup tool from Windows:

%windir%\system32\cleanmgr.exe