It seems that the offer requires a minimum $75 item, and applies only to things shipped by Amazon, so filter by ‘eligible for Amazon Prime’.
One example is Tumi items, search Tumi and then filter by Mens or Woments Clothing to get only items eligible for the discount, and also filter by eligible for Amazon Prime. Items that come up should be eligible for the discount.
The Travel Fund says you should be able to get an additional discount as well using code AZTWENTY.
Nothing I want to buy at the moment, but for example one Flyertalk member reports buying this Tumi laptop bag for $112 with free shipping.