A budding entrepreneur.... how wonderful!! You do not "convince" people..... you persuade them by highlighting the attributes of your product..... so.... what makes your wallet different, better, cheaper, safer, than all of the other wallets out there? Any chance that you can introduce a way for people to individualize their wallet? Also, I would go to where the cruise boats are.... tourists are pretty good about purchasing something novel from a local.... especially if they know that you are supporting yourself in this way. I would figure out how many feet of duct tape is needed for one wallet. then I would find out how many wallets you can make with one roll of tape. Then I would divide that by the cost of the tape.... and that would give me the cost of supplies. Once I had the initial cost, I can see how much profit I make per wallet. You may be able to lower the price of your wallets if you know the actual monetary output for supplies. Good Luck on your venture!