Reloading steel cases
Yes, Golden Bear has steel cases. SOme of this stuff is new production, and some of it (namely, 7.62x39, 9mm Makarov, etc) is military surplus that has been repackaged. Wolf does this too. You will definitely find a cost savings with steel-cased ammo.
And yes, it can be reloaded, BUT there are some things you need to consider. Unless you have the time and money to burn, it generally isn't worth it to try and reload Berdan-primed ammo (brass or steel case). That's just IMHO.
Second, I'm not a metallurgist so I can't get into the exact physics, but you need to consider that as cartridges are fired, they change dimensions slightly. So, as you resize them, crimp them, fire them again, etc., the metal undergoes what is called 'work-hardening'. Same thing happens if you take a solid wire or piece of metal and bend it several times in the same spot. It gets brittle and cracks or breaks. Different metals (brass, steel, aluminum) have different tolerances and characteristics. I wouldn't reload aluminum cases for this reason. Steel can be done, but since it's generally harder than brass it takes more effort. You can overcome the 'work-hardening' issue somewhat by annealing the cases, which involves heating and quenching them; but you have to consider that it most be done correctly, and it takes time, which goes against why most people reload their ammunition.
So, let's deal with Boxer-primed steel cases. Thanks to Wolf and Bear, they're common and cheap. The primary factor you need to keep in mind is that steel is harder than brass. It is more prone to work-hardening, requires more effort to size, trim and prime, and a steel case probably won't last as long as a brass case under the same conditions. Also, unless you're using a revolver, consider that you also have those steel cases causing slightly increased wear on the action and chamber of your guns. I reload steel cases with no problem, but I use light loads and keep a closer eye on the condition of the cases.
Also, with .223 ammunition, consider that brass for that is VERY common. You can probably score a great deal on some once-fired brass (note, that if it's military brass, the primers may be crimped in which requires a little more work before re-priming the cases), and the once-fired brass will still outlast steel cases. Like I said, I reload steel cases without a problem, but for the greatest savings in cost, time and effort, I'd either go with once-fired brass or buy some surplus .223 ammo (of which there's a lot to be had) and reload the brass from that. Have fun, BE SAFE and good luck!