Shared shuttles are cheaper, and that’s the honest starting point. On a route like San José to La Fortuna, a shuttle seat typically runs somewhere in the $50-60 range, versus $160-200 for a private vehicle covering the same distance. On shorter hops, like Liberia to Tamarindo, the gap looks more like $25-35 versus $90-120.
So what does the extra cost actually buy? Three things, mostly: timing, stops, and who’s in the vehicle with you. A shuttle runs on its own schedule, picks up and drops off at other hotels first, and goes where the shuttle company decided to go. A private driver leaves when you’re ready, can add a stop you actually want, and it’s just your group the whole way.
If your priority is the lowest possible cost and you don’t mind someone else’s schedule, a shuttle is a completely reasonable choice. If a free hour to stop at a lookout, a working farm, or a small town matters more to you than the savings, the math tends to favor going private, especially once you’re traveling with more than two people and splitting the vehicle cost.
There’s no universally right answer here. It depends what you’re optimizing for on this specific trip.