you could drill and tap the hole for a larger size screw... but, my math says that at the price you mentioned, you are looking at abour 40 bucks for 300 screws. Let's say you drrill and tap for a 2-56 screw. You will probably pay 5 cents per screw, for a total cost of 15 bucks. If you don't already have the tap, throw in a few extra bucks and now you are sitting around 20$. I say for 20 bucks, it really aint worth the time, and I would just buy the atlas screws. Even if you did find the correct screws from another supplier, I doubt they will be less than 5 cents a piece.
Kevin