"Invest" is the correct word. You take on a complex software with zero guarantees, zero support, outdated documentation and basically have to do it all yourself

"Invest" is the correct word. You take on a complex software with zero guarantees, zero support, outdated documentation and basically have to do it all yourself: analyzing the quality of the thing, making it seaworthy by developing a deployment if needed, testing it, migrating it, etc etc. The boss's boss's eyes glazed over when I said free and open source but he got a reality check when I told him no, significant cost accrues elsewhere.