Re: Advice needed

Whatever you think, and double it, add a contingency, and consider the client relationship: how much time and input do you think he or she is going to want?

Perhaps an approach to consider would be to go onto a per-hour rate, and give a time estimate spelling out all of your assumptions, with the rider that if those assumptions don't hold then the time and cost needs might change.

If you give an all-in fixed fee on an open-ended, unclear job spec then trouble may be ahead.