postage/shipping not included — indicates the shipping cost is not included in the listed price and will be charged separately.
商品価格：1,000円（送料別）
Price: ¥1,000 (shipping not included).
ネットで安く買えたが、送料別で結局高くついた。
I got it cheaply online, but because shipping wasn't included it ended up costing more.
送料無料になる条件がない場合は、表示に「送料別」と書いてあることが多い。
If there's no free-shipping condition, it's often indicated as 'shipping not included'.