The Department of Homeland Security (DHS) proposes to adjust certain immigration and naturalization benefit request fees charged by U.S. Citizenship and Immigration Services (USCIS). USCIS conducted a comprehensive fee review, after refining its cost accounting process, and determined that current fees do not recover the full costs of the services it provides. Adjustment to the fee schedule is necessary to fully recover costs for USCIS services and to maintain adequate service. USCIS plans to increase fees by a weighted average of 21 percent.
If you are planning on filing for an immigration benefit, I would do so before the prices go up. For example Adjustment of Status based upon marriage to a U.S. Citizen will go from $1,490 to $1,760. Nationalizations will go from $680 to $725
Here is the notice published in the Federal Register