Another way to test the viability of your idea for market acceptance is to develop a small amount and sell it. 

 

If consumers flock to it then you know that you have something that others are willing to pay for. 

 

If it does not sell then it is an indication that it is something that you should not move forward with at least in its current form. 

 

It may mean that you have to tweak the product/service before moving forward. 

It may also mean that your idea does is not the solution to a problem that consumers are looking for.
Entrepreneurs usually make the mistake of producing too much of their product in the beginning only to be left with a large inventory and out of cash when the items do not sell.
Don't open up a storefront right away or sign a lease to a warehouse.  Try to sell the items through your website first and gauge consumer response.  You can reach millions of customers by opening online storefronts in Ebay, Amazon, Etsy, Shopify, etc.
This option minimizes your risk.  Only a very small investment is required.