I would just pick up a pack of screws from Amazon myself.
The normal ones are about $6 for a pack of 50:
https://www.amazon.com/StarTech-Replacement-Mounting-Screws-Standoff/dp/B00028CAIK/
And a set of black ones are about $7 for a pack of 20:
https://www.amazon.com/SUPER-PC-Computer-Motherboard-Mounting/dp/B00YXKLX90/
If you want to go for it all, you can get an assortment set of computer screws for about $10:
https://www.amazon.com/Screw-134pcs-Assembling-Computer-Case/dp/B01BXT03KI/