I have 18 (100 count) unopened boxes of black Ondura 3" philips head screws. Can be used on Ondura corrugated roof panels or any other similar brand. They have a rubber washer to prevent leaks. Go to Home Depot.com for more description and pic.
Home Depot did sell boxes of 55 hex head screws for $12, so roughly $21 / 100 screws. At the time I paid just under $18 a box. Currently out of stock.
I special ordered too many and too late to return. Selling for $15 per box of 100 screws or buy all 18 boxes for $225.