TSP has the math about right. The margin for reloading .38 Spl is enormous. The only cartridge which is even more "profitable" is .44 Magnum.

$35/500 for 158-grain LSWCs (includes shipping, MBC)
$21 for a pound of Bullseye dished out at 2.8gr per
$22/1000 for primers bought online for zero hazmat
------
$5.02 per 50/box

The cheapest CCI Blazer aluminum-cased TMJ garbage on MassAmmo goes for $12/box, plus $12 flatrate shipping which we'll just forget about for fun. My state doesn't allow online ordering unless it's received by an FFL, which can cost anywhere from "free" (I still have to drive to the guy and hope he remembers he likes me) to $10, to as much as $35 or $50.

So that's $7 a box saved for most of you. A hell of a lot more for me. Remember, I either pay a $35-$50 tariff for every shipment, or I burn 3-4 gallons of gas and 45 minutes each way driving to the good FFL.

Now, I can easily reload 150/hr on my turret press. If you figure in the inordinate amount of screwing around, organizing, and maintenance I do, I'm looking more at 100/hr to produce really high-quality, matched-headstamp ammunition. So I can save $14-$21 in an hour, and shoot some really great ammo instead of embarrassing factory garbage. And in my situation, that 1.5 hours I didn't spend driving to pick up a case is worth 225 reloading rounds by itself.

Stepping up to .357 Magnum loads only costs another $0.50 to $.0.75.