3,005. Consecrating Future Goods
Hilchos Arachin Vacharamin 6:25
Let’s say that someone is selling gourds, eggs, etc. and a buyer comes, takes one and leaves. If the price is fixed per item (e.g., $1.99 each), it’s as if the price was agreed upon, so the seller can’t consecrate the gourd because it’s not in his domain (i.e., we consider it to have been sold, even if not yet paid for). However, if the price wasn’t fixed and he consecrated it, then it is consecrated. This is because it’s still considered to be in his domain, since we assume that the buyer didn’t take it with the intention of stealing it (but rather that it’s a sale still in progress).
Hilchos Arachin Vacharamin 6:26
One can’t consecrate something that hasn’t yet come into existence. For example, if a someone says, “Whatever my net will bring up from the sea is consecrated” or "The fruit that my field will produce is proscribed," he has said nothing.