Look into IDEO (a world-class design firm) and their prototyping methods. They're really good at getting to the core of an idea with the limited materials available (as an example: they prototyped a surgeon's tool with a sharpie and some tape.)
DIY with a screen recording product like Telestream/ScreenFlow(Mac) or TechSmith/Camtasia(PC). Record a walk through of your web app (or mocked up screens), while also recording yourself doing the voice over.
We building a web app, now we want to make story telling demo video. So what are the low cost options we have ?
Effective means to get people to add detail to their questions?
what product? toothbrush or condom?
If I was on a limited budget and had to coddle together a demo condom.. use a waterballoon..? Is this a live demo or?