What do you hope to make? A customer need has to exist first. If you hope to make 2 lb parts 500 at a run you're in for a mean learning curve as tens of thousands of garages across the US are occupied by small part time machine shops bidding on those jobs and doing it at prices that compete with third world country prices (plus duties, shipping etc.) If you already know of a need that exists, buy a cheaper machine and start making parts, ( before somebody beats you to it) slowly working your way to newer machines that require less personal time.
If a job shop is your goal, which is much easier to get in to, than plan on a slow ( 5-6 year) growth into full profitable business. But job shops require long hours, low labor return at least during the early years, ability to do almost any repairs that metal can possibly need ( welding, cutting, bending, straightening, machining, etc etc etc...)
A million dollar machine won't automatically get you customers even if it's the only one in the country. Customers are the hard part, and inherently afraid of any new machine shop.
Best advice I can give is avoid debt at all cost!
Second, decide what type work you hope to do and research the profit margin.
You can likely get into business for yourself, how much you make or spend keeping it afloat depends on your research before hand and work ethics after.
Machines are no trouble and plentiful if you have a good job lined up to justify the cost.