A bag of shot costs anywhere from 35 to 55 bucks for 25 pounds. I can reload trap loads - 1 oz loads, with international powder, figure 8 wads and Remington primers to accurately duplicate a nitro 27 load, for about 4 bucks a box, with used nitro 27 hulls. They go for about 8 bucks a box new. Generic trap loads still cost me 3 - 4 bucks a box, and can be purchased for 6 bucks a box or so depending on brand, and sale prices.
Not much difference when you factor in the bulk costs of reloading supplies.
Where you REALLY start to save is when you are making fast hunting loads. You can reload THOSE for about 5 bucks or so a box versus the 20 - 25 a box you will pay for them at the local stores for GOOD hunting loads. ( 1.5 oz, 1500 FPS #4 loads, or similar)
