MARK MULLENS

Need to hire me? Let's see what we'll need to communicate to make sure everything goes smoothly:

1. What the content is.
Is it a commercial? Corporate video? Maybe a documentary? Is it educational?

2. Tone/delivery/style/role/audience.
There's more to a voice over than just the "sound". Whether it's a certain mood for a fashion campaign, or a story you're trying to tell for a company video with a point of view, more clear information will help me deliver exactly what you're looking for. 

Reference material, such as a video or music is also very helpful. 

If there is a specific target audience (e.g. students, mature audiences, etc), this can drastically alter how a voice over is delivered to cater to that audience. 

3. The usage. 
This is how price is determined. A voice over used in a large TV commercial is going to command a higher price than an elearning module for a very specific sector, as it'll be exposed to more people, increasing the value of the voice over.
 
If you're unclear about how much you should be paying, I strongly suggest the GVAA Rate Guide for North America, and the Gravy For the Brain Rate Guide for UK, Europe and Latin America. The Voice Realm Rate Calculator is also extremely handy if you have very specific usage.