Assessing interest in a product before company start up

I am currently considering setting up my own business and have begun my research into relevant courses, grants, aids etc that I can avail of through enterprise board etc
However before I start I would love to know if people would actually be interested in my product.
Anyone any ideas or experience in how I should go about this? is there an online facility, surey tool of some sort? I am trying to keep my costs down so marketing/ advertising agency is a no go.
My product exists in the market already (limited use in this country), would be a low cost consumable item for people to use, just wondering if people go for it.

Any advise would be great.
Thanks

There are tons of out there. SurveyMonkey seems to be the most popular, but you can also , or install something like LimeSurvey on your own website if data protection is important. I've used LimeSurvey myself, it's a nice piece of software.