I am intentionally not providing specific figures here as every project differs in terms of scope of work. For example, some projects are more technical and require considerable research to execute efficiently.
What I will provide are the three common models that most of my clients choose from when engaging me:

This is perhaps the most cost efficient and hence popular engagement model with the majority of my clients. An example of this could be quoting $X for an X number of blog posts or media releases a month for X number of months. The longer and more frequent the engagement, the lower my charges get, in contrast from the standalone once-off project one. Each deliverable includes 2 iterations/rounds of edits.

This has proven to work for clients who require once-off or periodic ad-hoc work, an example being website content. This also helps clients who would like to evaluate my standards of work and/or explore if we are a right fit to work together moving forward. I provide a quotation that includes 2 iterations/rounds of edits.

This is understandably the least popular model as customers/clients often question or are unable to ascertain why certain projects would take a stipulated amount of time. I usually quote a figure based on my hourly rate and amount of time necessary to complete it and provide a breakdown so that there is full transparency from the get-go. In all honesty, this works best for agency work where I come in as an external consultant/content creator/copywriter to function as an in-house staff member when resources are short or expertise is lacking. Once again, this includes 2 iterations/rounds of edits.