Please forgive me I extremely new to this.

I am trying to build a database server that will be able to take customer information and store it into a database. My questions are what is the best type of server for this job? (Initially I want to start relatively small in terms of a server) Also, I want to run Microsoft Server 2003. So what is the best database software to run if all I want to do is take in customer's info and information about what they want to purchase. I would appreciate any help. Thanks.