It all depends on your definition of 'free'.
If you go on the internet, download the software and install it on your server then it was 'free'. But if you then hit an issue and your server is down for two days because you have no vendor support for the OS then rather than being free it has actually cost your company quite a lot of money.
Whether open source or proprietary, nobody should run a commercial enterprise on something that isn't backed up by credible and responsive vendor support. And, to quote the old proverb, 'you get what you pay for...'