it was only 6 or 7 years ago when AVGAS was only around 20 cents more than than the price of regular unleaded petrol at a city petrol station.
And it was about 17 years ago when AVGAS was about 6 to 7 cents/litre
cheaper than regular Unleaded.
I was then living in a house on a regional Airfield, working for a Regional Airline and had a TA22 Toyota Celica with a somewhat 'worked'
twin cam engine.
It pinged like hell on regular Unleaded and went like hell on AVGAS!