When I got into the sport, my thinking was "anything below $0.33 a shot is perfect, below $0.50 is acceptable, above that I'll want to find a rich widow". Cheaper brands were at $0.23-$0.30 a round last summer, quality brands were about $0.40-$0.45 for 9mm 124gr FMJ/TMJ.
Now I'm seeing budget brands at $0.36-$0.48 per shot. 124gr Blazer Brass and Federal around $0.40, Wolf at $0.36. There still some cheaper budget ammo if you get a case of 1000, I've seen some Barnaul steel cases at about $0.27 and CCI aluminum cases at $0.32.
That's why I'm getting into reloading now. I shot almost 2400 rounds out of a Cx4 at 50 yrds last year and discovered there was little point in shooting the cheap ammo anymore: it's not consistent enough to let me improve my technique. I never know if a flyer in a group is me or if it's the ammo, and they tend to go in every direction. If I can't diagnose the issue, I can't correct it. At $0.50 and more per round for the good stuff, reloading 9mm has definitely become desirable. And I'm planning to get into other calibers this year too, where the ammo costs are higher than 9mm... makes doubly more sense to reload now!
Initial investment is a pain, though... workbench, progressive press, dies and plates, brass tumbler, accessories... no less than $1500 in all because I have not much temptation to spend less now on just the basic stuff and spend more later to replace it all anyways. I rather bite the bullet and keep the equipment as-is for 10 years.