An "offer" to sell an item on an online auction site generally is treated an invitation to negotiate.

Question

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An offer on an online auction site is usually considered an invitation to negotiate, rather than an actual offer. This is because the seller can choose to accept or reject any bids placed on the item, and may set a reserve price that must be met before the item can be sold. Therefore, until the seller accepts a bid or agrees to a particular price, there is no legally binding agreement in place.

An "Offer" to Sell an Item on an Online Auction