It depends. If your parcel contains a refrigerator (!?), it could be pretty expensive. If it's just a 20-30 lbs, 2X2X2 ft or so, it will cost you a hundred dollars or so (maybe $150 or $200 but not...
It varies greatly depending on the weight and dimensions of the parcel and how soon you would like it to get there. To give you a rough idea, a 1kg parcel would cost around $35 to send via Air Mail....
It depends on your internet plan. If you are on a plan which measures the amount of time you are connected then it depends only on how long it takes you to write the email, which shouldn't be too...
USPS site has a postage calculator on homepage (below). It depends on service, package weight and dimensions and zone shipped to. first class in for 13 oz or less only you can use parcel post which...
That will depend on where you are and where you are sending it to. Go to your local post office and they will be able to tell you, once you give them that information.