Reddit reviews Hauppauge Hd Pvr Usb Hi-Def H.264 Video Capture Device,High Definition Usb 2.0 Video Capture

Link For The PVR

Most people who post commentaries on youtube use the Hauppauge HD PVR, which is way out of your price range. I know there are cheaper options out there, but most of those will not get you 720p video(pretty much standard for youtube commentaries now).

If possible, you could try to find someone who would record the videos off your fileshare for you and then upload them somewhere for you to download them.

For PC gaming you need to buy a legit copy of Fraps. For console gaming you'll need to spend some money and get THIS or something similar. Most Lets Play videos though use emulators and some form of Fraps or similar. Last resort is that you could use http://www.screencast-o-matic.com/