USCIS proposed fee increases in 2020 which would have made significant changes to the prices for many important benefits like citizenship, work permits, and waivers. It also changed policies like allowing people to request a fee waiver based on having low incomes.
On September 29, 2020, a US District Court Judge issued an order stopping the new fee increases from going into effect. On December 28, 2020, the government withdrew an appeal in that same case. It is not expected that the USCIS fee increases will go into effect at this time.
The typical fee for the form I-601A provisional waiver is $715. Most applicants will also have to pay for the immigrant visa fee before filing, which is $325.
The current prices for different forms and benefits can be accessed at uscis.gov and by using the USCIS fee calculator.