Reliable cheap or free DNS service?

Solution 1:

DNSMadeEasy was what we looked to for this purpose. No API (AFAIK), but a simple, if somewhat ugly, web interface does everything I need (lots of RR types, reverse zones, etc...). $60/year for 10 million queries/month. Check them out!

Solution 2:

I've used zoneedit.com for 6 or 7 years now and never had any problem with them. I guess this should fit your definition of reliable whatever it is...

Their pricing system is the following:

You buy credits whenever you want (credits doesn't expire). Managing a DNS zone and using zoneedit.com dns for serving it for one year will cost you 1 credit by slice of 200Mb network traffic usage.

The more credits you buy, the less it costs:

1 credit = $10.95
10 credits = $49.95

You can have the details on their faq.

Solution 3:

For a few years, I used EveryDNS for free DNS service. They encourage donations by removing the limits on the number of domains and records, but the defaults are quite generous. At the time, they only offered the basic records: A, CNAME, MX, NS.

I have since moved to using GoDaddy's DNS provided with my domain registrations, so I don't know if they've improved the service to include more record types.

Solution 4:

MyBind is a pet project of mine.

You can create unlimited zones and records for free;
You can edit the TTL for your zone and each record;
And, it has two geographically dispersed DNS servers.

MyBind zone editor

Solution 5:

For around 100 domains you could run your own cheap primary server with all your DNS records and then get the Secondary DNS service from Gradwell.net to sync and serve?

By a cheap primary, a virtual server host would work fine.