Order powder and primers from Powder Valley.
I use Montana Gold bullets. You can get them from Montana Gold directly or from Jake at Rocky Mountain Reloading (He's a member here).
I'm sure there's one powder that can be used for 38 and 357 but you might want a second one for 45. I'm not really sure though, I don't load any of those cartridges. Certainly there's one that would work, but maybe not optimally in all 3.
Still happily answering to the call-sign Peetza.
The problem, as you so eloquently put it, is choice.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.