You can find a variety of companies online to help you with your market research. For example: Sundale Research's (sundaleresearch.com) primary goal is to provide new and mature businesses with objective, accurate industry data and market analysis on a wide range of topics. Their market research is intended to save you time and money while keeping up with industry trends. But your idea may be so new that you may also need to talk to potential customers, host some focus groups, talk to an ad agency, or maybe even make a prototype and float it past some people. Be prepared to spend the time. Remember, it's not about the Plan but the Planning.
What's more important, sales or profit? Profit is what generates your salary. You could actually make more profit with less sales. Less sales could actually be less work. The most important thing for a business is to make money. That's profit. Now some might say, I don't care so much about making a lot of money. I like the freedom of owning a business. Well that is probably true, but if you don't watch your profit, you might lose that freedom. It's always amazed me how most businesses, even very large ones, talk about how much their sales are. You hear comments like, that's a บꯠꯠ company. But what's a บꯠꯠ company if it has no profit. Now I do admit that 2% net profit of บꯠꯠ is a lot bigger than 2% of ũꯠꯠ but most likely the large one carries a lot more headaches too.