As someone who has a number of vintage machines they are an option and asking for donations is a great idea. That assumes the machines are in working order or you can service them to the point of functional.
I also have several low end Brothers. One at my house and one at each of my sons. They have never gone out of time or given me the first bit of trouble. They sew through anything (fleece, fur, velcro, canvas, etc.) and are not fussy about thread. I wonder if some of people saying they are bad have had any real experience on them. Plus if you save the receipt you can return them if they don't work out.
There are a lot of us on this board who have very good things to say about the low end Brothers. I would not discount them if that is a possibility, maybe for one or two, to supplement with other machines.