I just received my Mac Mini from Amazon and used the free shipping option.
I ordered the Mini late on Monday, October 22 and it shipped via USPS the following Monday, October 29. It was delivered on Thursday, November 1, for a total of 8 business days.
I also bought the Apple Keyboard on the same order as the Mini and that shipped on Tuesday, October 23 and was delivered on Wednesday, October 24. So, it is hard to predict when Amazon actually ships the Super Saver orders, but I think it is safe to assume about 5-7 business days for delivery.
This is from the Amazon Super Saver Shipping page:
"Please note that your order may take an additional 3 to 5 business days to ship out from our fulfillment center. Transit time for Super Saver Shipping orders is 5 to 9 business days after shipping."
http://www.amazon.com/supersavershipping
Hope this helps,
Cris