This is a volume business and there are lots of people playing in the same space. The money to be made - as evidenced by GoDaddy's domain sign up process - is in selling the "ups and extras". The problem with profiting is that the threshold to entry is so low and with templated sites it's so easy for someone else to set up shop.
If you have $89. to burn it's probably a cheap adventure ride. Open shop, hunt for traffic, keep constant track of what competitors offer and who knows? You might only lost $49. ;0)
What about eNom?
The problem I have with eNom, is that I just don't understand their multiple reseller and subreseller and subresellers of the subresellers ...
How much is for being directly a subreseller from them?
It is not published in their website.
I've seen clones of eNom's website, I wonder, which kind of reseller are this, are API? or template based?