I bought a used Mec 9000GN for $350 and with lead shot being the biggest variable, I can get reclaimed shot at $25/bag and use 3/4 oz for skeet and 16 yard trap which is more than enough to break the targets at all stations with authority even on 3-4-5.
Prices after tax for components bought locally
3/4 oz shot at $1/lb = $1.17/box
19g powder @ 160/8# = $1.357/box
$10/500 wads = $0.50/box
$30/1k primers = $0.75/box
Total of $3.77/box or a savings of $2.71/box over store bought shells @ $6/box with tax.
so it took me 129 boxes to pay for itself which I easily ran through in the first year. After that, it's pure savings and when you tend to shoot 4 rounds each time you go out, you save quite a bit even with 12 gauge. Loading buckshot or slugs is no different and costs the same per shot as a target load because you can used the reclaimed shot to cast with. For me, I found the best benefit from tailoring my loads to both cycle my gun properly (Remington 1100 with an IC barrel) and still be easy on my old shoulders. Where I shoot, Remington Gun Clubs are everywhere and I've stopped collecting them because I have several 5 gallon buckets plus a couple of leaf bags full of once fired hulls.
Shooting the 12 gauge gun is now as light as shooting a 28 gauge gas operated gun and the days I shoot 6 rounds of skeet, I don't even notice it other than it being a long day of shooting.
If you shoot trap or skeet with regularity, I seriously recommend a progressive loader. One shell per pull is a whole lot easier than 5-6 pulls per shell and restocking 4 boxes of shells takes a lot longer with a single stage press.