What is the difference between Bargain Purchasing, Tender Purchasing, and Comparison Purchasing?

To determine the purchase price classification Purchasing can be categorized into bidding, inquiry to purchase, than the price of procurement, bargaining procurement, pricing acquisition, and open market procurement.　1, Purchasing by Invitation to Bid (Purchasing by Invitation to Bid) is the material procurement of all the conditions (such as the name of the material, specifications, quantities, delivery date, payment terms, penalties, bidding deposit, bidding vendor qualifications, the date of the opening of the bid ......) set out in detail in the newspaper announcement. Bidders shall pay the bidding deposit and participate in the bidding within the specified time according to all the conditions of the announcement. In order to open a tender, at least three or more vendors must submit bids. In principle, the bidder with the highest bid will be awarded the bid after the bid opening. However, if the bid is still lower than the reserve price, the purchasing officer has the right to announce the abolition of the bid or to negotiate with the supervisory staff for a negotiated price.　2、Purchasing at Inquiry Price (Purchasing at Inquiry Price) Purchasing personnel select creditworthy vendors to explain the purchase conditions and inquire about the price or send a request for quotation and urge the other party to quote the price, and then purchase at the current price after comparison.　Purchasing at Inquiry Price means that the purchasing personnel will ask several manufacturers to provide prices and then decide on the manufacturers to purchase after comparing the prices.　4, pricing acquisition refers to the purchase of a huge amount of material is not one or two manufacturers can all provide such as railroad sleepers or the tobacco of the Commissary, or when the lack of the material on the market, you can set the price of the cash purchase.