Ask HN: What was the CAC of your first customer?

While listening to Tyler King from Less Annoying CRM he mentioned that the CAC of their first customer was something around $1000 (paid ads, they unsuccessfully tried other channels). I have previously given up on an idea when I didn't get any leads using $50 ad spend.

Is it normal to spend a lot of money on experimenting with marketing before seeing any kind of customer reaction? What was the customer acquisition cost of your first customer?