The asking price for translation depends mainly on two factors: the language pair and the type of document being translated.
The language pair refers to the language you are translating from, or the source language, and the language you are translating into, or the target language. For example, my translator working from English into Urdu charges less on a per word basis than my translator working from Spanish into English. It may have to do with the fact that the former is living in India where the cost of living is relatively low compared to the U.S., where my Spanish to English translator resides. I did the following Google search: "average rates for translation language pairs," and the first link to appear was for a list of aggregate rates on Proz.com, a highly respected translator community, to which I belong. Viewing it will give you an idea of some, but certainly not all, of the variability in rates charged, just in terms of translation from English into other languages:
If the document type is highly specialized, like a medical journal article or legal document, for example, a translator will usually charge more than if it is something very general, like a pop culture magazine article. The same Proz.com platform allows you to select a "field of expertise" (e.g., Medical: Pharmaceuticals) and compare translation rates across language pairs. I have provided the following example:
The third factor that will often affect the asking price for a translation is the deadline. If the job is needed in a hurry, there is likely to be a higher charge for a “rush job.”
In actuality, a single translator may have a whole range of prices that he or she charges, depending on the parameters of a given job, which is why this question is so difficult to answer directly and simply.