Here‘s a very interesting offer. The US Mint is releasing special presidential dollar coins, and offering free shipping in order to increase circulation. You can order up to $500 worth of each president, and it seems like four presidents will be released each year. While it’s not a ton of miles, it’s a pretty good amount for doing nothing, assuming you could practically use the dollar coins. I actually find the dollar coins to be pretty neat and can think of a practical use for them, so am seriously considering placing an order.
Also, if you wanted to, you could just take them right back to the bank and not even have to spend them, but that’s not necessarily within the spirit of the system.
(hat tip to this FlyerTalk thread)