1) Use Google AdWords keyword tool to gauge the size of the market. Find something with >10k searches (Local, Exact match type) https://adwords.google.com/o/Ke

1) Use Google AdWords keyword tool to gauge the size of the market. Find something with >10k searches (Local, Exact match type) https://adwords.google.com/o/KeywordTool‎ https://adwords.google.com/o/KeywordTool‎ 2) Build the product. Make a sales page. Offer a 30 day trial on all accounts. 3) If someone signs up, you have 30 days to figure out billing. Couple of points: - No, this is not a great method. Getting out of your house and talking to real people is always better. - Any effort is better than nothing. And unless you have a product in the wild which someone could sign up for, you are doing nothing. - If you have time to comment on HN, you have time to build an MVP Also checkout Gumroad.com. Its about the easiest way possible to bill people. Once you've sold a few units, then you can worry about finding a better deal. Do it!