Free CGI scripts are available like sand at the sea. However functional scripts which can be installed simply are rare. A very good script, which fulfill all mentioned requirements is Every Auction. With this script you can start an online auction on your own homepage. The only requirements are the fact that you may use free Perl CGIs on your web server and the mail settings of your provider are known (e.g. path to the sendmail program). The script is simple to set up and works nevertheless very professionally and looks also great at relatively little expenditure.