WRT the accounting...
I can't load quality shells for $3.07 a box. Maybe I haven't tried hard enough, but I'm looking at $3.50 minimum and more like $4.00. But I'll take $3.07 as my working number. The closest Sporting Clays range to my house charges $35 per 100 rounds. To go farther just burns up a lot of gas, which costs $3.00/gallon. So let's take $35/100 as the price to shoot Sporting Clays. At $3.07/box, that's $12.28 per 100 rounds, or $1228 for 10,000 rounds. That 10,000 rounds would cost $3500 to shoot, if it's Sporting Clays. Skeet is cheaper, but I believe we're talking about Clays. Add at least $200 for tips.
Total cost $4928 for 10,000 rounds, round numbers would be $5000.
So, if I pay $4.80/box, that's $18.60 for 100 rounds, or $1860 for 10,000. $3500 for tickets, $200 for tips.
Total cost $5560, round numbers $5600.
600 bucks is 600 bucks, but we're looking at a 12% savings here. That might be worth it, or not, but it's a fact that someone who is looking to reload in order to shoot for a dramatically lower overall cost will be disappointed. And that's worth looking at, before spending too much money on equipment.
Personally, I think there's genuine value in understanding what's inside a shotshell. Experience with handloading has intrinsic benefits. That doesn't necessarily mean that loading every round I shoot has a good cost/benefit ratio. YMMV.
And Fiochhi's 7/8 oz. loads work great IME.
As I said, I haven't seen STS shot for sale in a while at any price. That stuff performs quite well. I'd reload if I got the stuff for a good price. If I'm loading mediocre shot, I can do as well with other loads. I haven't shot Gun Clubs in a while. Federal Top Guns work pretty well, as do some others, and I haven't paid more than 5 bucks a box for any of the few hundred boxes of practice ammo I have at home right now. Haven't tried the Kents yet, but they sure work well for the guys who have -- very good shooters.