Your audience/fans/customers don't buy products. Every time they click "Complete This Purchase" they are buying the person who is selling that product -- you.
If your audience is sold on you, you can sell shitty products (for a while, at least) to them and they will even rationalize its shittiness for you.
If they're not sold on you, you can have great products that gather dust on (virtual) shelves.
If you're having that problem you can turn it around in a few ways. Maybe you're looking at the wrong audience (who just don't want what you're selling). Maybe you as a person are missing something (the hardest one to self-diagnose -- personal development audios and reading books will help this). Maybe you have the wrong product or it's in the wrong packaging (problem it solves, naming, getting the word out).

Ultimately, you have the power over any circumstance as soon as you decide that you do. Selling is just a transfer of emotion -- whoever has the stronger level of emotion at the time of the exchange (of ideas, thoughts, words, emails, etc.), has the influence over the other.