Maybe charge a estimate fee, and if they go with your services, you can refund that fee on the final invoice.

Great reminder by OP. I spent about three years building up my clientele and putting in some major time on my own dime. But because of that work and effort, I now can make money replying to order emails. I make around $1,500 a month doing this, which is nice. I’m on year 8. So in my own personal experience, passive income is possible, but the phrase has been hijacked by get rich quick schemes and con artists. It’s been twisted and made to believe no work is involved in creating passive income, when in fact it is the exact opposite. Lots of NON-PAID work upfront.