I never got too deep into it, but I enjoyed ~10 hours of it before getting distracted by other games. It felt more like a park business simulator like Roller Coaster Tycoon, rather than an elaborate park and ride designer like Planet Coaster.
It's totally worth $15 if you want to scratch that itch.
That's much higher than normal. A quick google suggests between $200-$500 is more in line with a normal student loan monthly payment, which is still a burden on someone just starting out.