Don't know where you are but in Lake Jackson we have Brazos Fasteners. They are an industrial supply house for stainless anything used to fasten things. They are used to dealing with non-industrial customers like us (will sell you 1 u-bolt or whatever) and their pricing is fantastic.
Their pricing allows me to change out to stainless when the galvanized finally gives up.
x2 on Brazos Fasteners. They are on Plantation Dr. in Clute. GREAT prices. That's where I stock up on stainless screws etc. 1/3 the price of home improvement stores.