That just depends on if penguins enjoy gatorade.
almost anywhere
There is no reason to sell an ice cube in Antarctica.
Mostly any stores that are department.... Walmart, Target...etc
The most likely and reliable source is the Gatorade website itself. You can have coupons emailed or sent to you that way. Also try searching chain stores that sell Gatorade, they will often have online savings and coupons that you can print out, take in, and redeem.
Honestly I like Gatorade and I don't have anything against them, but they have no other flavors so they add the word "frost" to make it sound cooler and sell more
Try Canada Only @ http://www.canadaonly.ca. They sell the 1.45kg cans of it. Here's the direct link: http://www.canadaonly.ca/products/Gatorade-Powder-Bulk-Can-1.45kg-|-Orange-Flavour.html
Nothing. There is no commerce related to Antarctic resources.
No. There is no caffeine in Gatorade.
general prosessing of gatorade
You'll find that the market for ice cubes in Antarctica is very small, and may not be worth your investment to attempt to compete here.
You won't be able to find a tent for sale in Antarctica, unless another explorer had an extra tent and was willing to sell it to you.
Gatorade