New vendors must click on the Supplier. Registration link and provide the following account information: Tax ID, Company Name,.Complete registration here to begin using Contra Costa County Purchasing. Vendors, please read this disclaimer prior to completing registration. CCTA uses PlanetBids for the procurement process. Visit PlanetBids to sign up, download the RFP and other documents, and submit proposals. Today's Date: Applications must be submitted 14 days in advance of the event date. Incomplete applications will not be approved. Register: Use the Vendor Registration Form to register your company. Below you will find all of our current open RFI, RFP, and RFQ bids as well as instructional videos for the budget templates.