This year, several of my friends and I found a week that we all had off and were free, and we booked a spring break trip to Cabo. We found some very reasonable flights on United that we decided to buy immediately. Instead of paying the full fare, I used my Amex Platinum's $200 Airline fee reimbursement feature to shave $200 off.
This is how you do it. I logged in to my Amex account to choose the airline I wanted my $200 in fees to be reimbursed from. Then I went to United's website and purchased a $200 gift card on my Amex Platinum. Using the gift card, I was able to book the ticket with United and pay almost half of what my friends paid for their tickets. Within a day, Amex credited the $200 back to me.