> As a certificate authority, one of the most common questions we hear from customers is whether they’ll be charged more to replace certificates more frequently. The answer is no. Cost is based on an annual subscription […]

(emphasis added)

Pump the brakes there, digicert. Price is based on an annual subscription. CA costs will actually go up an infinitesimal amount, but they’re already nearly zero to begin with. Running a CA has got to be one of the easiest rackets in the world.