a statement or conduct which invites each recipient to make an offer or enter into further negotiations

a way of saying, "Make me an offer

An invitation to open negations with a view to forming a contract. Displaying goods for sale is an invitation to treat, not an offer

In contract law, an invitation to treat (invitation to bargain in the US) is an action by one party which may appear to be a contractual offer but which is actually inviting others to make an offer of their own. The distinction is important because if a legitimate contractual offer is accepted by another, a binding contract is immediately formed and the terms of the original offer cannot be further negotiated without both parties' consent. An invitation to treat may be seen as a request for expressions of interest.