This is expensive but you can buy 100 for $24 and they are stainless:
https://www.boltandn...PD_BwE#641=4605
Or a box of 1000 in zinc for $35.29:
https://www.aimsindu...g-scr~291176105
But if you went to someone like Newcastle Hi Tensile Bolt, you'd probably buy 100 for $5.