As per the Indian Contract Act, 1872, an offer is the final expression of willingness by the offeror. He intends to be bound by the offer as soon as it is accepted. But where the party without expressing his final willingness, merely invites offer from the other person, it is an invitation to offer. Invitation to offer is a mere willingness to negotiate.

Invitation to offer comes before an offer.

For Example: X asks Y “ Will you buy my laptop for ₹30,000?”. Now this is an offer as Y can accept or reject it as soon as it is made. But if X tells Y that he needs 5 laptops and what is the best price at which Y could supply those laptops, it is an invitation to offer.