28 cents powder - It requires about 70 grains of RL-15, H-4350, etc, so 100 loads per pound
3 cents primer
70 cents a bullet - 50 / box for $35.00
60 cents new brass, but if you have fired brass, you obviously don't have that cost.
So, it costs about $1.60 US for new brass loads, and $1.00 for reloads in fired brass.
If you drop down to a lighter bullet, and a milder load of H-4895 for deer or practice, your cost falls to about $15.00 a box.
You could shoot cast lead at 1,800 fps for a light hunting load, with very little powder, for maybe 45 cents a round.
And believe you me, a 250 to 300 grain bullet at a MV of 1,800 will flatten big deer at 100 yards. Have not done it in a .375, but with a .45-70 and .444