Many entrepreneurs have great ideas. But not all great ideas are a viable business, one with a reasonable chance of making a profit. That's where proof of concept helps, testing the idea before investing a substantial sum. In the software business this is referred to as building the minimum viable product; e.g., programming just the basics of an app so that targeted users can play with it and give the developer feedback. In the food business, this usually means preparing the item in your own kitchen and offering it for sale at a farmers market, where you can gain insights into packaging, pricing, usage patterns and hopefully receive some consumer testimonials. If your idea involves a service, the usual practice is to start small and make personal presentations.
Do what you can afford, learn from the experience and fine-tune your offering.