How to judge "Salary commensurate with experience"?

I have an interview for a position with the salary listed as "commensurate with experience". How do you foot the question about what salary you want, if they ask?
I am finding it hard to judge what is reasonable as it is not the exact same position as I'm in now and it is a community organisation (so probably very tight budget) and no comparable salary scales.

10 years implies a significant level of competence and experience.
A week may be a long time in politics - its no time in terms of job experience.
That's the range, with say three years implying a reasonable level of competence.