The filing fee for Form I-765 is $410, effective 12 a.m. Eastern U.S. time, December 23, 2016. A deadline for 2017 has not been listed yet. See USCIS.gov for details.
If you are now on a 17-month OPT (Optional Practical Training) extension, you may apply to extend your OPT period for an extra 7 months. You must file form I-765 (Application for Employment Authorization) by August 8, 2016. This form must be signed and submitted with the correct fee. For more information on the 7-month extension see 7 Month Extension. The current filing fee for form I-765 is $385. You should check the filing fee before sending your application because filing fees may change.
The rules for STEM extension application changed in 2016. The change allows those who qualify, to apply for a 24-month OPT extension. Students who are currently on a 17-month STEM extension may apply for an additional 7 months but must meet the August 8, 2016, deadline. For more information on the 24-month OPT extension see STEM OPT.