View Public Works' open solicitations, and learn more about how to register as a supplier and submit a bid or proposal. Vendors and suppliers interested in doing business with Allegheny County can review open solicitations for Purchasing and Supplies bids on the Bonfire website.Please fill out ALL fields on the Bidder Registration form. BID PROPOSAL: Please see the form located in section 004123. Description: Invitation for Bids. All prospective bidders are required to execute the Bid Schedule, Bid Bond, Proposal, Non-.