Ask HN: How do you price something to a client?

I've been developing a tool in my spare time to help make finding student properties easier at my university. One of the steps in making this a successful venture is to get the local estate agents on board. I have emailed one of them my pitch and got asked the question "Please could you let me know what sort of funding you would be looking for to develop this?". How would you go about answering this question? initially the project was going to be B2C with a premium option however B2B is looking promising, but I'm stumped.