More food for thought
If you can find a local commercial reloading business, you may be able to buy ammunition in bulk for even less than $21 per 100. Ask you local police department training officer where they get their training ammo.
9mm is one of the most difficult cartridges to make savings on. If you shoot .357 magnum, 45 Colt or almost any rifle cartridge other than 223/5.56, the savings are more substantial.
On the other hand, many people who began reloading for economy find that reloading itself is a satisfying pastime. Some find the relaxation of the repetitive operation to be enough of a reward. Kind of like knitting, but more manly.
Others find that they can craft better ammunition than the mass producers.
Some find a great deal of pride in rolling their own and being independent of the mass producers.
You can also assemble ammunition tailored to your particular needs. I have a friend with a 500 Smith & Wesson who loads (along with full-power loads) some pipsqueak loads (350 grain bullet at 800 feet per second) that shoot like 22 rimfire out of that heavy gun but, do the math hit harder than 45 ACP. Really nice for letting someone not familiar with the gun shoot something that will not knock them on their butts.
I have run calculations on my ammo costs and find that for most of my calibers, I can save money rolling my own, even if I factor in the cost of my loading equipment, the components AND pay myself a wage equal to my regular job. I doubt if I could come up with a positive number for 9mm if I include ALL those costs.
On the other hand 500 Smith costs over $3.00 a round in my town while components cost $0.75. My friend (who shoots the 500) with that round can save $100 in an hour of reloading (box of 50).
So, if you only contemplate reloading for 9mm and are interested only in cost savings, your Dad may be right. If you give him a 45 Colt or 44 Special for his birthday (too late for Christmas this year), you may get him to change his mind without even offering an argument. Expect a reloading press for YOUR birthday.
Good luck.
Lost Sheep
p.s. Anywhere near Ft Walton? I was stationed at Hurlburt Field for a while.