Buyers of 16GB Google Nexus 7 before price cut can score refund from Asus or Google
Play Store, those who purchased it within the 15 days prior to the price reduction will receive the difference in price as long as the refund request is made within 15 days after the cut in price. As a result, those who purchased the 16GB Google Nexus 7 tablet from the Google Play Store on or after October 14th will receive $50 back no later than 14 days after you make the request for the refund.
Once Google introduced the 32GB variant of the Google Nexus 7 priced at $249, the 16GB model of the 7 inch tablet was cut from $249 to $199. To request a voucher from Asus or Google, click on the appropriate sourcelink.
source: Asus, Google, The Verge via Phandroid