There are 2 machine shops I have a 'special exemption' where they allow me to climb in the bin and extract steel and aluminum that I can use. Most of my 3/16" and 1/4" plate came from one shop... They have even 'sold' me stuff off their racks for a specific project -- i.e. for free, because it was there for more than 10 years.... I've also purchased stuff off their off-cut racks at far more than scrap price without blinking, those few extra dollars have allowed me to get hundreds of pounds of steel bits for free.