Either find a partner with money to help you out or use services like Kickstarter.com

If it was me, I would first learn everything I need to know about launching a transactional website (if you are able to sell your product online and ship it ). Websites like Shopify.com make it possible for anyone to get their product online.

From there, if you do not have any money for ad spending, start using social media and other sites where your target clients hang out. Get involved in those communities. This will help you get discovered.

I would try my best in selling the product within my network first so that when I decide to raise money for marketing, I actually have some numbers to show for it.

Hope this helps.