I don't think that you can hand load 12 gauge much cheaper than buying new, if you factor in the amount of time it takes to load, etc.
You have to load very high volume to make it feasible.
However, if you are shooting sub gauge like I do, it is a viable option, for sure.
The price of 28 gauge ammo is staggering to buy , even in volume.
here is where I buy most of my stuff.
http://www.bilozir.net/
Components sometimes go on sale in stores, m but it seems everything is getting expensive these days!
Shot and powder isn't getting any cheaper, and wads are getting hard to access for private guys to import , as well.
Cat