face to face coupons

[kinkyropes]

Howdy,

 

I travel the country doing trade shows selling stuff to people face to face. Sometimes I ever happen to run out of a spicific product at one of these shows. If a customer asks for an item that I simply didn't bring enough of, I would like to give them a 'coupon code' that will give them free shipping. I figure I shouldn't be charging ~them~ for a mistake that ~I~ made.

 

What I would really like is a kind of hidden link. For example, have a little spinning earth in the upper right corner that most customers wouldn't notice. I would tell the customer at the trade show 'go to my website, click the little spinning earth in the upper right hand corner, and type in the word 'free123' and that will give you free shipping.'

 

Is there any contribution that I could change or modify simply to let me do this? I am ok with PHP programing but I simply dont know my way around the file system that well. If not, does anyone have ideas on some other way I could do face-to-face coupons?