Shipping: I do combine shipping.
The current USPS shipping charge which is also my cost. If you buy more then one of my listings; please let me invoice you so you can receive the real shipping cost. If you do not let me invoice you and pay the shipping for each item you buy, you will normally get a refund if you have over paid.
Stainless fasteners are all the same.
Unless there is special tread or length; stainless metric screws are all the same. They come from the same plants overseas which are primarily in Europe,China, Phillipines, and Taiwan. So whether what ever type of fastener it is, you might as well buy it from the seller who gives you the most for your money.