It turns out that there is something that can compete with free: easy
From a Times.com article on the hackers behind BitTorrent, Gnutella and libdvdcss - http://www.time.com/time/specials/packages/printout/0,29239,2032304_2032746_2032903,00.html
They do provide scripts that take care of most of the work but ther is still more involved than a web front end.
For example you make changes in batches of records, and they can be create or delete. So to change an IP in an A record you make an XML document with both a delete request and a create request with the new value then poll the API for a sat us of in-sync.
Its a shame - it would be nice for them to throw in a the first billion!
Which seems quite good for a globally hosted DNS service.
Only potential limitations are that its listed as "beta" and that as far as I can tell you have to use the scripts in the Route 53 developer tools (or write your own) to manipulate the zone and do the initial set up.
On topic - This combined with the free year of a micro instance will allow you to put a proof of concept together for only the cost of your time.
From a Times.com article on the hackers behind BitTorrent, Gnutella and libdvdcss - http://www.time.com/time/specials/packages/printout/0,29239,2032304_2032746_2032903,00.html
So its price reflects this both good and bad stability.
On the other hand Apple has a track record of coming up with almost totally new markets which it can dominate and take the lions share of the profit, or find a niche to exploit in an existing market - ala iPhone. So it's price is speculating that they can keep finding these huge new profits in addition to the huge profits they already make.
tl;dr Apple is like a giant profit finding machine.