Ask HN: What should you do when you have an idea but no money to fund it?

I and a few friends had an idea recently that most probably won't change the world but, if executed properly, can help people and small businesses in smaller towns compete with the bigger names. Problem is as we started working on this idea, we realized we will need a considerable amount of money (maybe not a lot by Western standards, but a lot to us) to get even a working prototype that people can just use. Most of us are barely adults, not industry veterans, so no one would fund us without a working prototype, we don't have the capacity to fund it ourselves. What should we do in such a case? Shelf the idea, come back sometime later when we can afford?