Virtual domain server

I have heard about two options for giving domain name, virtually setting the domain name, (may be virtual domain name server) , that is for eg. clicking www.xxx.com will be done by pointing to any other site like, www.myname.com/xxx. Is it possible. Or the other options for buying domain name in bulk, is it feasible. Which of the two option is best as I am thinking of starting a web server along with DNS. Looking forward to hear from you. Looking forward for your help as you have always given me, thank you.