Car Service Tycoon puts you in charge of a garage. Cars come in needing work, you repair them, and the money buys better equipment, more mechanics and a bigger workshop — until the place largely runs itself and you're managing rather than turning spanners.
It's an idle tycoon game with a car-collecting layer on top: alongside the business, you accumulate vehicles, which is what gives the progression a visible reward beyond a rising number.
Automate the bottleneck. Hiring a mechanic for whichever station has the longest queue does more for income than any upgrade elsewhere in the garage.
Yes, in your browser's storage, so the garage is there when you return on the same device.
Yes — a light browser game with nothing to install.