as others have said there's many donation based retreats available.
I can also offer a rough line-item of where money goes, on retreat that have a sticker price:
1.) Cost. Many communities don't have their own retreat facilities and are thus basically booking room and board at a venue. Every venue has different amenities, costs, and profit models, but even a retreat site that operates at low margins as a gift, where retreatants share rooms and do substantial amounts of their own cooking and cleaning, even that is easily going to top $50 per person per day, while having a basically "resort-ish" experience where the group has single rooms and very little chores can approach $200 per day (in California).
2.) Back into the community who volunteered to organize it. There's probably 100-200+ labor hours behind every retreat, which is done in part so the teachings and practice can flourish, but is also motivated by the need to keep paying rent and other expenses on the community's primary practice and meeting space.
3.) To subsidize others. I think the teacher or leader of almost anything typically pays a reduced rate or nothing in recognition for their skill and leadership. Additionally it's not uncommon for part of the "profit" from retreats to be rolled into a scholarship funds for those whose ability to contribute is less than the bottom line costs, when the amount from donations doesn't match the need.
Also, Buddhism, and even more so mindfulness isn't necessarily concerned with conforming to our ideas of minimalist or anti-materialistic. While it's true that renunciation is often presented as part of the Buddhist path, retreats meet people where they are in their readiness to leave their comforts behind. A 5 - 14 day retreat might offer such comforts as the presence of a swimming pool or lounge furniture during break times so that people don't feel like they've joined monastic boot camp. There's many different things that get called "meditation retreat" and generally they're each well suited for different people at different times.
I can also offer a rough line-item of where money goes, on retreat that have a sticker price:
1.) Cost. Many communities don't have their own retreat facilities and are thus basically booking room and board at a venue. Every venue has different amenities, costs, and profit models, but even a retreat site that operates at low margins as a gift, where retreatants share rooms and do substantial amounts of their own cooking and cleaning, even that is easily going to top $50 per person per day, while having a basically "resort-ish" experience where the group has single rooms and very little chores can approach $200 per day (in California).
2.) Back into the community who volunteered to organize it. There's probably 100-200+ labor hours behind every retreat, which is done in part so the teachings and practice can flourish, but is also motivated by the need to keep paying rent and other expenses on the community's primary practice and meeting space.
3.) To subsidize others. I think the teacher or leader of almost anything typically pays a reduced rate or nothing in recognition for their skill and leadership. Additionally it's not uncommon for part of the "profit" from retreats to be rolled into a scholarship funds for those whose ability to contribute is less than the bottom line costs, when the amount from donations doesn't match the need.
Also, Buddhism, and even more so mindfulness isn't necessarily concerned with conforming to our ideas of minimalist or anti-materialistic. While it's true that renunciation is often presented as part of the Buddhist path, retreats meet people where they are in their readiness to leave their comforts behind. A 5 - 14 day retreat might offer such comforts as the presence of a swimming pool or lounge furniture during break times so that people don't feel like they've joined monastic boot camp. There's many different things that get called "meditation retreat" and generally they're each well suited for different people at different times.