If you are thinking of filing an application for trademark registration or a patent, you've likely thought about fees. (If not, here is the place to look.) Now you get a chance to share your thoughts with the USPTO. The USPTO is a fee-funded organization, and the revenue generated must support the operation, but cannot exceed the estimated cost of operations.
Thus, the USPTO regularly evaluates fees for patents and trademarks, and asks for input on the proposed changes. The most recent announcement is here, which also has the history of fee adjustments, and the email addresses for direct communication with the USPTO about the latest fee setting information.
There will be a hearing on the proposed changes to trademark fees on September 23, and you have until the end of September to submit a written comment on that or the proposed changes to patent fees directly to the USPTO.