I'm a member of the SSC. I've always saved more than the shipping charges with my membership.

I also buy items for friends. That way we get enough of an order to meet the $150 free shipping limit.

I have a spreadsheet saved in my computer. I've been tracking Towers' promotional sales offers for about 5 years now. I've got their pattern down pretty good and I know when to buy--most of the time.

It is true that the frequency and "generocity" of the promotional offers are closely related to the economy.