Stop guessing, see this site:
http://www.handloads.com/calc/loadingCosts.asp
Based on this my cost to reload 9mm (115 gr fmj) is $5.27/50. This is based on components purchased in the last 90 days. My powder cost is based upon 8lb containers and my primer cost is based on buying 5k at a time.
But - I use free brass scrounged from the range. I always come home with more than I shot.
Jeff