A PhD program will get you free tuition. Don't ever pay for a PhD program at a US university. If you do a PhD program where you get a Masters along the way, then you could get a Masters for free and then drop out if you want. There are a lot fewer paid tuitions for Masters students, a lot of these students have their companies pay full tuition.
As long as you can get into a PhD program, it gives you a lot more flexibility and is cheaper than a Masters program.
Right, but PhD admissions is naturally much more competitive. But leaving financial aspects aside for a moment, is a PhD worth 4-6 years for a future career in the business world?
No, you should only do it if you will find the learning itself personally enriching or you desire a career in academia, a corporate research lab, or a hedge fund. You should only do it if you really want to, not because it will pay of at some time in the future.
As long as you can get into a PhD program, it gives you a lot more flexibility and is cheaper than a Masters program.