Postage charges vary depending on exactly what it is that you are planning on shipping. Large letter prices are currently $3.00 up to 125g, $4.50 for 126-250g and $7.50 for 251-500g. To be shipped as a large letter, the measurements of the item including packaging must not exceed 260 x 360 x 20mm. If the dimensions are greater, then the article becomes a parcel. If the weight is over 500g then the article becomes a parcel.

Without knowing what the product is, there's no way of calculating the most cost effective shipping method. For example, a tail light globe is a small item which weighs less than 125g - but it is 45mm x 28mm x 28mm, so it becomes a parcel. By the same token, a box of ball sinkers is also a small item which is within the measurements - but it weighs over 500g, so it too becomes a parcel... but then 2 DVDs can be shipped side by side in a polymailer as a 126-250g large letter for $4.50