If you buy too many things and you have to send it through the mail, you can go to the post office. If you don't have a box, most post offices sell boxes of all sizes.
"Do you sell boxes here?"
"Can I buy one of those large boxes?"
"What is the largest box you sell?"
"How much is the box?"
If you are sending it to a different country, you have to fill out a form. You can either wait until you are ready to send it, or you can fill out the form before going to the counter. They will have blank forms available next to the counter for anyone to take. On the form, you have to specify what you are sending, how much it costs, and the address of where you are sending it to. After filling out the form and packing your box, you are ready to go back to the post office to send it.
Because the box should already have the address, they will not ask you where you are sending it. The first question they usually ask is how you want to send it. You can send it by boat, and a variety of air mail.
"How would you like to send it?"
"How much is it for air mail?"
If that is too expensive, you can ask if there is anything cheaper.
"What is the cheapest way to send it?"
Because you are sending a box, they have standard questions they ask everyone.
"Are there any perishable food items in the package?"
"Are there any fragile items?"
They also ask if you want insurance on the package. It's not that expensive so you can ask how much it is.
"Would you like to insure your package?"
"Would you like insurance?"
"How much is it?"
After everything is determined, they always ask one more question.
"Do you need any stamps today?"
That is basically it. Let's cover some general sentences you might need to know in the post office.
"How much does it cost to send a regular letter to Korea?"