Scrap metal yards often have 19" racks as part of their stock, delivered by
the demolition blokes on their trucks and sold on a price of about $2.00 per
kilogram.
Gateway steel has a scrap yard next door that I use in Brisbane and there is
also Sims.
Won't say that every rack is clean or straight, but I just get the bits I
see that might be useful one day...... You would be surprised what is
returned for recycling, local dumps are another source for cheap electronic
bits.
Peter