buying Apple proudcts in The Miami Airport

There does not appear to be one.

Apple stores are generally located in upscale Malls and upscale downtown areas to generate LOTS of high quality repeat traffic.

Stuck in an Airport is not a good location for repeat traffic, even in Miami.

The other issue you may face is that Most Macs are currently 'build-to-order' and very few are available for 'off-the-shelf' delivery.