Thanks for playing!
1. I just tried, buying car should work. Maybe your character didn't have 50 coin, or it wasn't standing near to building. I think the area to trigger the action is probably too small, will make it larger in the next update.
2. That's a very good point. I actually hope the game would last around 3 ~ 5 minutes, so I purposely increase the rate of money production after 5 minutes, in order to makes the player who are in advantage to end the game faster. But it seems to backfired as the DPS of the character couldn't even keep up the speed of production.
3. Haha, I never expect someone would play the game that long to see all building producing money non-stop.
Thank you so much for the feedbacks, it's impressive how far you playtest the game and spot the problems!