a. All purchases, contracts, or agreements where the cost or contract price exceeds the sum of $25,000 or, after the effective date of P.L. 1999, c. 440, the amount determined pursuant to subsection b. of this section shall be made, negotiated, or awarded only after public advertisement for bids therefor and shall be awarded to that responsible bidder whose bid, conforming to the invitation for bids, is most advantageous to the Hackensack Meadowlands Development Commission, in its judgment, upon consideration of price and other factors; provided, however, that such advertising shall not be required when the contract to be entered into is one for the furnishing or performing of services of a professional nature, or when the purchase is to be made through or by the Director of the Division of Purchase and Property pursuant to section 1 of P.L. 1959, c.40 (C.52:27B-56.1), or through a contract made by any of the following: the New Jersey Sports and Exposition Authority established under section 4 of P.L. 1971, c.137 (C.5:10-4), the New Jersey Highway Authority established under section 4 of P.L. 1952, c.16 (C.27:12B-4); the New Jersey Turnpike Authority established under section 3 of P.L. 1948, c.454 (C.27:23-3); the New Jersey Water Supply Authority established under section 4 of P.L. 1981, c.293 (C.58:1B-4); the South Jersey Transportation Authority established under section 4 of P.L. 1991, c.252 (C.27:25A-4); the Port Authority of New York and New Jersey established under R.S. 32:1-4; the Delaware River Port Authority established under R.S. 32:3-2; the Higher Education Student Assistance Authority established under N.J.S. 18A:71A-3. Any bid may be rejected when the commission determines that it is in the public interest to do so. Any purchase, contract, or agreement where the cost or contract price is less than or equal to $25,000 or, after the effective date of P.L. 1999, c. 440, the amount determined pursuant to subsection b. of this section may be made, negotiated, or awarded by the commission without advertising and in any manner which the commission, in its judgment, deems necessary to serve its unique interests and purposes and which promotes, whenever practicable, full and free competition by the acceptance of quotations or proposals or by the use of other suitable methods.