Except for ones that increase revenue or allow offsetting costs in other areas.
Having used MySQL and SQL Server, there's not much of a contest. You can do everything in both, pretty much, but you can do it more quickly and more maintainably in SQL Server. The developer tools are all really good, the functionality is outstanding, it requires less care and feeding. There are plenty of cases where the added money isn't worth it. But your time has value, too.
It's been my finding that experienced MS SQL developers tend to hire out at a much greater cost than experienced MySQL developers... MS SQL Standard also starts at $3,700+ USD per core (and a minimum purchase of 4 core license, I believe), with a yearly SA fee on top of that. You could use Express, but it's missing many features - SQL Agent for instance.
Edit. I understand that it weighs against development time but that is a different matter than money in the bag.