Not sure where the OP is looking, but it's easy to find a full set (four) for not a stupid amount. You'll probably pay more in shipping than the screws cost you. Get enough other things in your cart and the cost will seem so much less.
IF you had the thread pitch, and such, you might be able to find them at your local hardware store (not a big box). The one down the street from me has a tray of 'gunsmith' screws in the array.
By the way MidwayUSA has a set of Wilson Combat screws for $8 for the set of four. These are 'specialty' screws, so you're not going to get them for pennies each. Get stainless and don't worry about them ever again.