Proposers must fully execute the NonCollusive Bidding Certification Required by. The Nassau County Bid Solicitation Boards are open to all registered vendors.Vendors that have not registered are able to view open solicitation opportunities. Before you start to fill out the bid form, read the bid carefully. Welcome to the Online Vendor Bid Site for suppliers and bidders interested in bidding opportunities for the commodities services and technology contracts. The Bid Proposal Form template is available for free. There are no charges for using this template to gather and evaluate proposals from potential contractors.