Because you are concerned about running your business on minimal dollars, the less expensive criticism will come from friends, relatives, and neighbors. It's far better to receive FREE criticism - than to pay for marketing research that puts a dent in your bank account, but doesn't yield any useful results. Be prepared to get LOTS of criticism and to put it to good use. Perhaps, a survey in your intended market - could provide some valuable information to be used in making your product better. This step will save you time and money.
Competition Check out how they are providing to their market.
There's no doubt in my mind, the expert in the field gets more business. Create a niche in your market and zero in on an idea that has potential for growth. People will remember you for it. If you can't answer the above points - and KNOW what makes your product more unique than the competition, you won't be able to relay that to your market. Refine your marketing Define the needs of your market by listening to the customers and understanding what their needs are.