Further to Andy’s answer above, the key question he points out is what proof of concept have you got on the idea and approach to executing the sell? getting a small local independent retail store (hardware store for example) to take your product on and you support it with instore selling/sampling how to use etc is so powerful to help you prove that it can sell and also the best way to sell it too. Will help you create word of mouth while informing you from face to face feedback is an invaluable way to learn, fail and fix/improve your idea and execution which the bigger retailers will ask of you even before what level of marketing and sales support you are giving. lots of small steps first help build significant momentum over time. All the best!