There’s a lot of things Travis ci could do. This is a great idea to help offset their costs, they could also have made their platform better to bring in more paying companies. They haven’t at all kept up with competitors as tooling and build processes have evolved in the past 9 years (namely easy to use docker-native test environments, and parallelization options for big codebases).
I agree with the parent comment, it’s bizarre to blame this on the new acquiring company and to be mad about this development. Travis ci has been asleep at the wheel for many years, and projects have been benefiting from it with huge amounts of free compute for years, but now the free money has run out.
Could be onetime payment or a recurring donation (charged together with whatever payments you have for the platform).