In Non-Profit (NPO) tuition free music schools the instruments are provided rent-free.  Normally only group lessons are the only platform with older children helping younger children with the basics.  Teaching artists (TA) are hired and by intention are working professional musicians, who are paid by the hour, and dedicated to the concept of providing free instruction.     

TA sacrifice group instruction time for any needed individual student attention, and so this is kept to a minimum.  With regard to inventory, there are rarely spare instruments, and so the routine sound or appearance issues are just endured, not repaired, except for dire circumstances and this is due in large part to both time and money constraints. As in the picture above, the old kids help the younger. 

These free schools help very deserving kids, and do incredible work.  Chicago has several hundred more violinists because NPOs are willing to take on the challenges of low pay and shoestring budgets, helping the kids who would always be the last in line.  

For four years I taught kid across cafeteria tables, before a changed the model and moved to St. Ignatius.  They taught me as much I taught them.  I learned begging from Damian Lugue, age 9 (below).  If you have fiddle in basement, we need it.