Here are some useful terms that may show up in the item name:
定金 / ding金：Downpayment (usually for a pre-order). Usually the listed price will be significantly lower than the actual price.
尾款 / 尾kuan: Remainder payment of a previous pre-order. You can’t purchase it if you did not participate in said preorder.
定做 / 定制: Make to order
无现货: No available stock (in other words, it must be pre-ordered)
If you’re not sure, just ask me or send your order and I’ll advise you accordingly.