Cast lead (commercial, 1k-2k piece purchase, $0.0625 / bullet)
Efficient powder
Free brass
Costs me about $0.104 / round. Or $5.20 / box (50).
(Buying in "case" quantities, I could run Montana Gold for another $0.03 / round, like BigJimP.)
Cast lead (mine - $0.019 / bullet)
Efficient powder
Free brass
Costs me about $0.061 / round. Or $3.04 / box (50).
And the above figures are based on using primers at $29 / 1,000. **
However... I'm currently using S&B, Fiocchi, and MagTech primers that cost me less than $14 / 1,000 (purchased 8,000 at a time, or 4,500 at a time for Fiocchi [1,500 ct 'brick']). So my actual cost is $0.015 / round, or $0.75 / box lower.
**(I know some of you have to pay more for primers in other parts of the country, but that's what I am currently seeing in the local shops that I visit. You have cheaper gasoline. We have cheaper primers. Such is life.)