Ask HN: Contracting – Request payment first or analyze app and submit proposal?

I am doing some contracting work on the side and was wondering how others go about a tricky situation.

The client wants me to analyze the application given a set of requirements and then submit a proposal and quote. However, the mere act of analyzing the app / code would basically be working. I know in other fields, a quote is usually given for free. For example, inviting over a contractor to evaluate a site plan.

So, should I pull the code, run the application, analyze the requirements and then submit a proposal or request payment to even begin looking at it?