I have spreadsheets for mine as well. I guess Im kind of anal about this, but its fun in that its almost a game (just how low can I get the price per round).
All costs listed include taxes (if applicable, right now powder sources are local, and tax rate is about 9%), shipping, etc. So Im actually comparing total / out the door cost . One area I know I can cut costs is on powder (at least, hypothetically.... I hear about magical jugs of powder, but so far they have evaded me): all powder to date has been purchased at local Bass Pro and in 1 pound packages. I also know that casting my own bullets would save me money, but Im not ready to take that leap (yet.... I said the same thing about reloading as recently as a year ago...)
9mm (unique, 115gr MBC LRN, WSP): $11.95/100. Cheapest I find locally, is TulAmmo @ $11.97/50.
.38 spl (unique, 158gr MBC LSW, WSP): $12.62/hundred. Ive not found any steel case stuff locally for this, so having to compare to WWB @ $43.60/100.
.357 (2400, 158gr Hunter's LRN, Rem. 5.5 primer): $23.87/hundred. This cost is unnecessarily high. Next time around I'll be saving another ~$5/hundred by sourcing bullets from MBC & buying primers in bulk. Cheapest local I've found is Amer. Eagle which runs around $32.70/50.
.45 (unique, 230gr MBC LRN, WLP): $15.55/100. Cheapest I find locally, is TulAmmo @ $18.52/50.
.308 (4064, 168gr Hornady HPBT, CCI LRP): $57.96/100. I found another source of powder that will save me around $4.36/100. Cheapest comparable load I find locally, is around $32.70/20. Im sure buying the bullets in quantities greater than 100 could shave off a few more dollars per hundred.