contact the seller, ive found that often they put shipping prices automatically as well as overbox things automatically, but if you know its something small and call they will put in envelope for you cheap.
bought a pilot jet for a robin carb, came in a box 6inches by 8 inches by 4 inches and cost 15 dollars to ship.... i was not informed of shipping cost when i purchased because i figured it would be obvious to put in a tiny envelope but nooooo
