I usualy find planting pots or 5 gal buckets. Real 5 gal buckets measured by volume, not nursery size ones.
Some occassional electrical supplies and equipment like, space heaters, power strips etc.
I really like those recycled building material supply stores, like Habitat for Humanity home supply. They are filled with everything from lumber, ducting and plumbing supplies, anything that comes from remodel jobs and demolitions.
I ran into around twenty of these 400 watt MH light fixtures at one of these places.(came from some school gymnasium) They had round metal reflectors with attached balasts which I seperated from the fixture, modified the hood and am using with an HPS conversion bulb. Cost me $20.00 for the light fixture and $95.00 for the bulb.