[H] mask your IP with a changing one

[Winterlight]

I know there are a few IT gurus in HWG so if there is a way to do 
this, you guys will know it.

 Is there a way to repeatedly mask your real IP address with another 
random one, that changes every time you log into the same site. To 
clarify... a site tracks visitors by IP addresses. You log on but 
mask your real IP address and display another one that is randomly 
chosen ,every time you log into a web site. So you could log into the 
same site numerous times in a day, each time with a new IP 
address.  It can be a free way or a paid way to do it.

thanks