Nothing is more frustrating to any sewist, esp a new one, is having to fight your sewing machine. I'd be inclined to be careful of the really cheap all plastic models. I wonder if folks from your church might donate toward the machines or have a machine to donate. Check estate sales too because that was where I found an older machine for $20. Worked perfectly. You might be able to get a good buy at a sewing or quilting store on a trade in. Will you supply fabric? If not the LQS might give the students discounts on fabric. That would be a good way to lure future customers.