Nonimmigrant and immigrant visa application fees has changed on April 13, 2012. The fees for most nonimmigrant visa applications and Border Crossing Cards increased, while all immigrant visa application fees has decreased. All visa applicants must pay the fee amounts in effect on the day they pay, including immigrant visa applicants who pay fees to the National Visa Center (NVC).

Fees that will decrease are not refundable - If you paid a visa fee before April 13, 2012 and that fee decreased, no refund.

Fees that will increase (only nonimmigrant fees) - If you paid your visa fee before April 13, 2012, you do not have to pay the difference between the new and old fee amounts as long as your visa interview is on or before July 12, 2012. Starting July 13, 2012, you will be required to pay the difference between the old and new fee amounts – no exceptions.

US Govt.