Like others have said, reloading 9mm/556 isn't where you really start to see savings. Sure, its cheaper... but compare the cost of reloading with premium components(bullets, brass, etc) vs the cost of match grade+ ammo which is essentially what you are loading, and you'll see the savings start to add up fast. Add in obscure or uncommon chambering, and its really apparent.
While 257 weatherby isn't exactly uncommon, I think the cheapest ammo you can find will run you about $2 per shot. For the nice Weatherby stuff with premium components its $4.25 a cartridge!
Reloading the Weatherby equivalent(bullet, brass), I'm paying about $1.20 each in components. Once I shoot through my first 50 rounds I'll have paid for the components and die set, and still have enough powder to load another 50.