Sources For Free Produce Boxes

I've found these useful, or should I say re-useful... for a variety of things.

The two good sources I've found are food bank depots which often have lots of banana boxes, and a YWCA foodbox program on their day of delivery which provides a lot of different types of boxes and even plastic fruit containers in the dozens

I would talk to the produce manager at the nearest grocery store. Long ago I used to work at a grocery store, and we handed out almost as many boxes as we recycled. The only things they kept were the waxed boxes because they were used for shipping off the unsold produce for composting.

In Toronto we have whats called the 'food terminal'. This is where wholesalers and resellers get their goods to flip for a profit. I assume most cities have something similar, and would probably be a good source for discarded boxes

i've gotten my boxes from:  supermarkets,chain stores,industrial parks, bulk stores(costco/bj's/price-club etc) produce stores(duh),
wine/liquor,beer distributors(tend to be smaller boxes). automotive stores (auto zone,pep boys)

some of these places use trash compactors so you're out of luck unless you ask inside for whats on hand,or for them to save em' for a day,hit or miss in this case.