I just went to click on the 30% coupon for the Garmin 530 and you apparently are ment to 

Unzip rxp-athome-2020.cpn  which does not appear to be able to be unzipped.

Not a great impression.

You don't unzip it. You use the Flight 1 ecommerce app to add the coupon before checkout. It's not an easy to use process the first time you do it. 

"not an easy to use process"  true dat,  I have tried numerous times and still cannot figure it out