The cheapest way to capture video from analog sources onto your computer -- EasyCap-style USB video capture devices are available for less than $5, and generally work acceptably well as long as you use the software and drivers that come with them. There are actually four different chipsets used in these EasyCap devices: https://linuxtv.org/wiki/index.php/Easycap The one I'm using here is the SMI Grabber SM-USB 007 version by Somagic, with the "Linkstyle" brand on it.
I used VirtualDub to capture this video, which caused an audio/video sync problem that I had to fix in video editing, but allowed me to capture interlaced video which I was then able to convert to 60fps using QTGMC de-interlacing. All other programs I tried were only able to capture video with rudimentary field blending de-interlacing already applied.
There is also a Mac OS program for EasyCap devices, although it reportedly doesn't work in El Capitan: https://bentrask.com/easycap/