An Internet-based competitive pricing and bidding transaction system includes one or more transaction processing servers that interface and communicate over the Internet with client computer systems of prospective online consumers, medical and professional/licensed services providers and a plurality of related information databases. The transaction processing system handles online communications and procedures for conducting auctions for delivery of proffered medical and professional/licensed services and maintains a registration database of service providers and online prospective consumers/bidders. Medical and professional/licensed services providers may include licensed doctors/nurses, licensed veterinary doctors/technicians as well as conventional homecare/hospice providers, physical therapy providers, babysitting and other professional caretaker services that can provided to/for man or animal. The online proffered services may include conventional medical treatment and/or veterinary services provided for animals, pets or other creatures. A professional license authentication/qualifier engine is provided which transparently and automatically researches, verifies and updates professional credentials, accreditations and background information of each professional service provider upon registration of that service provider with the transaction system, and makes that information available to prospective registered bidders online.