There are as many reasons to invest in shotshell reloading primarily you will be able to make a better shell by using "Hard shot" Hard shot or high content antimony shot (4% to 6%) can only be found in Winchester AA, Rem STS and Federal target loads. These days this ammo is selling for on average $15.00 a box or more when you can find it.
As a coach for the National Scholastic Clay target program i have seen many a clay bird hit, moved, orange dust
knocked off the bird clay target and not broken....not even a sliver of a piece. Hard shot would have broken the bird.
Since the pandemic shot shell shortages began used progressive reloading machines specifically Hornady and MEC have been selling for absolutely crazy prices. As suggested above purchasing a single stage MEC reloader
is your most viable alternative to get started...if you do.
As far as components, powder is slowing showing up yet you will have to monitor the internet sites every day for availability for a 4 pound or 8 pound tub of powder. It seems the only shotgun primer readily available is the Cheddite 209 (made in France) for $65.00 plus per thousand. Hard shot varies from $50.00 to $60.00 per bag. Wads are not an issue. Back in 2019 Winchester offered a rebate on sleeves (5,000) of 209 primers of $32.00
netting the cost down to $135.00 per sleeve, Presently Ballistic products is selling sleeves of Cheddite primers
for $361.00 including haz mat and shipping.
If I was you would I invest in a reloading set up....the answer is yes. May I suggest you start out with a MEC single stage reloading press and "Shop" for powder and primers. An excellent source for used reloading machines is using "Search Tempest" which allows you to search by state on Craigs List for MEC reloaders.
The powder and primer shortages should ease up in 2023....or so we are told.
I bought my first shotgun in 1970 and along with it, my first shotgun reloading press, a single stage Honey Bair. A few years later I joined a local Trap club mainly so I could learn to hit flying targets. There I got into league shooting, and later into ATA competitions where I was shooting and reloading 10,000 shells per year. Even before I reached half that many shells, I figured out that with a progressive press I could completely load one shell per stroke instead of the six strokes per shell on the single stage loader. I still have that Honey Bair press set up on my bench that I use mainly for the couple of boxes of hunting loads that I now shoot each year.
Since the OP's son is currently shooting beyond his home club's shoots, I would strongly suggest a progressive loader.
I currently have a work friend selling a Hornady 366 shot shell reloader for $500 so that sorta has me thinking about it. Not sure if that’s a good price and/or good press?? I think he said it can load both 28ga and 12ga. I could have misunderstood him too.
I bought my first 366 reloader in the early '80s when they were made by Pacafic. I think they were less than $150 back then. When I switched from mainly shooting Trap to Skeet in the late '80s, I needed to also load 20 and 28 gauges and .410s, so I bought a 366 loader in each of those gauges. I have had excellent luck with those reloaders and figure that I have reloaded somewhere between 250,000 to 300,000 shells on them.
As far as I know, Hornady no longer makes the 366 reloaders, but they still have parts for them.
The 366 reloaders come set up for one gauge, Die sets and the shell holder plate can be bought for other gauges, but changing them is very time consuming and a pita. You're better off with a separate reloader for each gauge.