I had a quick look on Interparcel…………… A package of 1kg ( thats the lowest weight on their site ) 4cm X 3cm X 2cm ……….
Comes to roughly CAD 40 to Canada and Aud 46 to down under. ( £25 & £30 respectively ).
Obviously bolts will weigh less than 1 kg and I recon normal post will be cheaper than that, but I need the exact weight.
At least this gives you a rough idea of your worst case scenario.
I recon normal post will be half that price, but thats an utter guess on my part .