If you can get yourself to Thailand and dont have an aversion to Buddhism there are Buddhist temples where you can go stay. Frequently you make a donation at the end of your stay with the amount being at your discretion.

An example near Chiang Mai in north west Thailand https://www.fivethousandyears.org/

Also look into Christian monasteries near you. I'm not Christian but spent a silent weekend at a Cistercian monastery and it was amazing. They suggest a donation but there's no charge. Only have to schedule a month or two in advance.

Why not just book a relaxing airbnb?

The Vipassana silent courses put on by dhamma.org are entirely free, run by volunteers. The popular locations are fully booked months in advance, but if you have a very flexible schedule you can get on the waitlist and be accepted right before the course, that is how I did my first one.

I've done two 10-day courses from them. After my first one I described it to people as like being in prison, never having gone to prison, but with less freedom than prison. But I still went back for a second time :)

Goenka’s 10-day vipassana retreats are not only free, but (at least when I took it) they would not even accept donations from those who hadn’t yet experienced the course: https://www.dhamma.org/

There are non-silent Buddhist retreats. Deer Park Monastery etc.