The only factory pistol ammo I ever bought was back in 1972 when I lucked into some WWII Canadian 9mm ammo for $2 a box (SCORE!!) back when 9mm ammo was $8 a box and there was NO cheap or bulk loaded ammo. You got your choice of Winchester or R-P, and that was pretty much it.
I did have some pistol primers with a Tecto sticker on them from the mid-70's, which were $0.99 per hundred, which is not mind bogglingly low, but I don't EVER recall primers going for less than that in boxes of 100. I was too poor to afford $1,000 primers back then...

I think a penny apiece was a nice, simple price, and no retailer or company had much incentive to go below that.