RollerCoaster Tycoon Adventures is hitting the Switch soon, and you'll be happy to know that microtransactions aren't part of the deal. In an interview with DualShockers, Atari's Mark Perloff flat-out denied the presence of microtransactions. That said, he did say the team is looking into DLC.
“No microtransactions. This is a premium game, through-and-through. For DLC, the RollerCoaster Tycoon franchise has a great tradition of awesome expansions, so that’s definitely something we’ve been talking about. For now though, we’re focusing on the base game.”