And this is exactly what you should be aiming to do. Create a product based on your OWN expertise and offer that advice for a fee. People are impatient creatures. Not tomorrow, not next week, but now. And if you can give them that information NOW, you're already half-way toward making the sale.
Automation is the key to success with any online business.
Your website is a VERY powerful selling machine. If you have the right knowledge, you can automate the process of virtually every business task. Once accepted, the payment is immediately added to your account and a thank you screen is presented to your customer. Automatically emails the customer thanking them for their order, and gives them information on how to download your online product. And you have no intervention with this process.