As for free, anything can be free if you try hard enough.
There's is a certain site that has a TORRENT of free downloads, but its sort of illegal and i wouldn't recommend it ^^;;
Anyway, now to talk about the actual software.
Fraps is widely accepted to be one of the largest ones, but i personally find its very limited, while high quality it tends to save all the audio to one track which makes it irritating, because it leaves less room for adjustment, it can only record opengl/directX windows, aswell as the stupid file sizes, a 20 minute recording of borderlands 2 could be upwards of 70gb, so unless you have stupid amounts of space to spare, i wouldn't really recommend it.
There is also camtasia, which is pretty good, because it actually has an inbuilt recording software, which means if your doing something like creating youtube videos (which im going to assume is why you want these) its great for balancing out the audio and tweaking the videos, and unlike fraps you can target the window to anything on the screen and (from what i remember) use seperate audio tracks.
Another one that i find quite good is bandicam, it will split audio tracks and does not create stupidly large file sizes, it has a feature that locks the recording window onto most windows that even something like fraps will not, and has adjustable quality, bitrate etc. etc.
It also has presets which will make them easier to load into things such as sony vegas.
I hope this helped, if you want any advice feel free to send me a pm or anything of the sort.