No no, you're wrong. It's $10 with the promo, but with an additional $3/month for the DNS service that's free in GoDaddy. A grand total of $46/year, hands up!
I am thinking about switching to Hover. TWiT has been pimping them lately. I don't see that hidden expense that this place has.
See the screencast here: https://dnsimple.com/intro
And API doc here: https://dnsimple.com/documentation/api
Regarding free domains, if I ever get to the point where I can sell domains as a loss-leader then I'd consider it, but almost every domain has a base cost, including ICANN fees and then markup from accredited registrars who offer reselling, and giving away something for nothing just doesn't make much sense to me unless there is a massive upside.