Amazon - DYWISHKEY 60 Pieces 1/4-20 x 3/8" 1/2" 5/8" 3/4" 1" Stainless Steel 304 UNC Threads Hex Button Head Cap Screws Bolts and Nuts Assortment Kit with Hex Wrench

This total was paid in two different transactions ($154.75 and $404.66). Used for prototyping.