Be mindful when packaging your parcels - especially for parcels going overseas or coming into Australia.
To keep postage costs down, use the smallest box possible. Postage costs are calculated on the cubic size of each parcel.
Be aware if selling worldwide of customs regulations. For example. Don't use used food boxes to re package your item. I have had items sent to me from overseas that were packaged in beef jerkey boxes. These items were automatically opened and inspected by customs officers because of the quarantine laws relating to importing food into our country.
So think hard and make the right decision before packaging your items.