The LeeLoader,,the little tube thing that you use a hammer/mallet to pound the hull into to size etc I would not consider unless you are really only going to load a box (25) or so every so often.
Yes it will load the rounds for you, but the process gets old very fast.

The Lee LoadFast,,the simple Press that has individual stations for sizing, priming, ,,then powder dispensing from a hopper,,then wad seating and then the shot dispensing from a hopper and finaly star crimping.

The sizing station uses a sparate sizing steel ring that you slip over the hull then place the hull w/ring into the sizing station.
Pull the press handle down and the ring is pushed down over the hull all the way to the rim which sizes the 'brass' portion of the shell.
This station also deprimes the case.

That ring will be 'stuck' on the hull at this point.
On station 2, the case is primed and that ring is also pushed free of the hull so you are left with a sized & primed hull and the now detached separate sizer ring ready to be used with the next case.

That primed hull is then run through the powder drop, wad seating, shot drop and crimping stages to get a finished shell.

The press itself is at first look rather flimsey for lack of a better word. Plastic abounds and it seems to flex when the round it run through each station.
But the thing does work! and it will produce nice reloaded ammo for you at a fairly good rate. Not quite as fast as a Mec 600Jr,, but only because of the need to handle that sizing ring separately.

The press comes with a bag full of powder bushings (plastic) as well as shot bushings. Easily changed out to adj the powder drop and shot drop to what you need.
I used a 12ga and a 16ga version of this press for a long time before getting a Mec9000 in 12ga.
In 16ga,,I still use the Lee.

In 410 I have a Mec600JR. Nice single stage press and have no complaints about it.

The 600jr and most all the MEC's have been offered in the past with conversion kits to other gauges.
But the time needed to convert and adjust plus the cost of a conversion kit really isn't worth it IMO.
Just get another MEC press in a dedicted gauge.

For 20ga, I was going to get one of the conversion kits for the above 410 600jr.
Then a 20ga Mec SizeMaster was offered up for sale at my local gun club for $150. So that's my 20ga press.

Shot is running about $50 to $60 a 25# bag right now.
Obviously, lower the payload to keep the price of your loads down.
No real reason to shoot 1 1/8 loads at SC or Skeet unless you're in a $$ shoot.
7/8 is fine.

I shoot 5/8 oz in 12ga and have no trouble at all.
I use a 7/8 load right out of the Lyman book that has a low PSI ( I shoot older guns).
Then reduced the payload to 5/8oz. I fill the leftover space in the hulls with cherrios or rice crispys for a good crimp.
Birds like 'em too I suspect.
Most all my shotguns are Full choke so there are plenty of #8 shot in the pattern circle for a 'kill'.

Wads are usually easy to find.
Brand name (Winchester, Remington, Federal,etc are the most $$,,buy the same as a 'clone' from Claybuster Wads at less money).

Primers are not cheap.
Not very long ago a Brick of shotshell primers was $25/$30
$70 and $80/1000 is a 'good price' ( 1000 primers in a 'brick')

The cheapest are usually the Cheddite brand also the ones that usually in stock. I think they are mfg in France.
Good quality, generally a 'hard' primer meaning the primer itself takes a good firing pin strike to make it go bang. Most will never notice it.Some vintage guns may notice a misfire or two with them.

The Cheddite primers though marked as a '209' size primer, they can be a .000 or 2 larger in dia than the standard US made 209 primer.
This doesn't cause any issue in seating them,, a press will simply seat them by swaging the primer pocket open that small amt the first time.

What can happen is that if you then go back to the slightly smaller US 209 primer in those previously reloaded hulls primed with the larger Cheddite 209,,the US 209 primer will be a loose fit. They can drop free sometimes after being loaded.
Fiocchi primers can cause the same issue.
But sometimes they are only thing around too.

I've been told there are 2 sizes of 209 Cheddites, the European (larger) and the standard US 209 size. But I haven't seen that to be the case.

Powder,,,can be very hard to find. Sometimes you just walk into a store and the shelves are full.
Powder is expensive when you do find it.
Some people say they got a good buy at $30/lb. I seem to recall it was just under $20/lb not long ago.
Doesn't matter,,you pay the price if you want the stuff

Be ready to switch powders. You favorite powder may not always be available. But some of the other all time standbys may be. Grab what you can when you can
If you happen to really like a new XYZ powder and have fallen in love with it,,that's great till it ain't avail anymore.
Then a can of RedDot might do just as well.

Empty hulls can usually be scrounged from ranges or friends that don't reload.
Our club has buckets of them that go to the trash every week.
After a SC tournament that comes around to the club a few times a year, there are 6 or 8 large drums of emptys waiting for the trash pick up. Most are new/once fired of all types.