[general_failure]

can someone clarify if revokation is free with letsencrypt?

Also, who pays for all this infrastructure? Mozilla?

[bracewel]

All the services provided by Let's Encrypt will be completely free, including revocation.

[vtlynch]

Not sure about revocation.

Sponsorship is provided by multiple companies, including Mozilla. See https://letsencrypt.org/sponsors/ and https://letsencrypt.org/2015/04/09/isrg-lf-collaboration.htm... for more.