A bid describes the requirement of the district accurately and completely in an attempt to describe materials in such a way as to enhance competition. Bids will be prepared in such a way as to avoid unnecessary restrictive specifications or requirements. Insofar as practicable, competitive formal sealed bids shall be used as standard procedures for all purchases, utilizing the following guidelines:
(1) Items to be purchased at any one time are greater than $500.
(2) There are sufficient qualified bidders to enable competitive pricing.
(3) The requirements of the purchaser can be described clearly, accurately, and completely.
(4) There is sufficient time to process the bid.