MouseSavers asks that this information not be posted on public websites. From a recent newsletter:
"The ticket offer listed below is EXCLUSIVE to readers of the MouseSavers Newsletter and is not available to the general public. Please don’t post the private link below in public discussion forums (i.e. the DIS Boards, TripAdvisor) or publish the link anywhere else. It is fine to share the link privately with friends if you send them a copy of the entire newsletter. Thanks!"
That being said, if you send me a PM with your email address I would be happy to forward you the latest newsletter with Undercover Tourist links.
I think it varies from month to month. I haven't been paying much attention lately since I don't have any trips planned for awhile. When you use the link from the MouseSavers newsletter, it takes you to the UndercoverTourist website and automatically prices tickets at the discount.