Sure! I started out poor and had a number of $100 and under cars during high school and college. Used cardboard in a few cases to make the heater nice and warm. Later and more prosperous, I had a Volvo - around 1963 model, egg-shaped, looked like a '47 ford sedan - that I had admired when they were new and eventually bought used. Those have the equivalent of a roller window shade that pulls up from the bottom edge of the radiator as you pull a cable under the dashboard. That works great for getting the heater working in cold weather.
And when I bought the YM240 15 years ago, I tried cardboard in front of its radiator to warm it up. The owner's manual specifies 5 minutes warmup before moving the tractor and I thought this would help it warm up. I soon decided to ignore that recommendation and just drive gently to the first worksite to warm it up so I haven't used cardboard since. Or ever idled it a full five minutes before starting out.
On a related note - you would think the AMC Eagle, a station wagon with full time 4wd and obviously intended for those who live in snow country, would have competent heat. No. I bought that with some 15k miles on it, nearly new. Both the heat and in summer the A/C, were completely ineffective. Consumer Reports verified what I had observed, they said this model totally failed to meet modern (1980's) expectations for both heating and cooling the interior. A $100 radiator shop cooling system tune up - replace thermostat, flush etc - made no improvement. I used cardboard in that car occasionally, as long as I owned it.
