California Code, Public Contract Code - PCC § 22104

(a) Contract awards shall be based on the proposal which provides the most cost-effective solution to the district's requirements, as determined by the evaluation criteria contained in the solicitation document.  The evaluation procedures may provide for the selection of a vendor on a basis other than cost alone.

(b) Evaluation of proposals for the purpose of determining contract award shall provide for consideration of a proposer's best financing alternative unless the district determines that a particular financing alternative should not be considered.

(c) A vendor may be excluded from proposal processes, if the vendor's performance with respect to a previously awarded contract has been determined unsatisfactory by the district, provided that the exclusion shall not exceed one year for any one determination of unsatisfactory performance and provided further that any excluded vendor may at any time during the exclusion be reinstated upon demonstration to the district's satisfaction that the problems which resulted in his or her exclusion have been corrected.

(d) To the extent practical, the solicitation documents shall provide for a contract to be written to enable acquisition of additional items to avoid essentially redundant acquisition processes when it can be determined that it is economical to do so.