The CryEngine version sold on steam is £7/$10 per month (slightly less if you buy a longer subscription), and apparently has no additional royalties if you commercialise your project. That seems very reasonable from the outside for any seriously interested parties, potentially just reduces support queries from casual users.

The free SDK apparently had a 20% royalties clause at the point of commercialisation, so this deal sounds much better.

http://store.steampowered.com/app/220980/ http://www.cryengine.com/get-cryengine/eaas-faq