A lot depends on what components you are using.
If you want jacketed bullet, new brass, basically like factory new ammo it would go something like this: $.14/case, $.12/bullet, $.03/primer, $.015/powder for a grand total of, call it $.31/round or $15.50 for a box of 50. This is all premium components.
If you buy once fired brass, use a plated bullet, you are quickly down to $.19/round or $9.50 a box of 50.
If you are willing to pick up your brass and load lead bullets you buy from a premium source, call it $.12/round or $6. a box of 50.
For maximum savings, you can cast your own lead bullets call it $.09/round or $4.50 a box of 50.
This doesn't include the cost of the reloading equipment, or your time of course.