A goPro pointed at the gauges, about as low cost as it gets. After that low cost is really not in the equation for data logging.
I did this for years....Tough to read the gauges with it as the car and gauges have some vibration. You would have to put the camera rigth up to them, and even then, you may miss a spike or other quick change....
https://www.youtube.com/watch?v=Znuo3jMUXTkThe next jump up, and one I have adopted is the Holley Stand Alone dash.....Not as easy to setup as I thought, but you can expand it to read anything you want to monitor. So far I like it.
