Here’s a selling formula that works miracle
1. Sell the initial products at a very low price (But not for free. That would not work)
2. Get the customers “habituated’ with your product. So that when the time comes for replacing / upgrading your product, he feels compelled to stick with you
3. Set a high price for the replacements, supplements and upgrades of that product, skim the market and make money.
This is a formula made world famous by PC industry. But it works for most of the technology companies, as well as non-technical ones. And much to the delight of manufacturers, it really makes a lot of business sense and keeps the cash registrar ringing.
One note of caution – Dont give your product away. The product that is available for free for customers does not create any emotional attachment. So he can replace it without much heartbreak.