An invitation for bid (IFB) or invitation to bid (ITB) is an invitation to contractors or equipment suppliers to submit an offer on a specific project to be realized or product or service to be furnished. The IFB is focused on pricing, and not on ideas or concepts. An offer given in response to an IFB is a bid, which should not be confused with a quote. “Offer” means a response to a solicitation that, if accepted, would bind the offeror to perform the resultant contract. A quote is not an offer and, consequently, cannot be accepted to form a binding contract.
If not stated otherwise, the contractor or supplier with the lowest bid is awarded the contract, provided that they meet the minimum criteria for the bid. This is in contrast to a request for proposal (RFP), in which case other reasons (technology used, quality) might cause or allow choice of the second best offer. An RFP is a request for a price from a buyer but the buyer would also expect suggestions and ideas on how the project work should be done. RFPs are thus focused on more than just pricing/cost, they entail a bit of consulting from the contractor or vendor.