You need to look around at stores near you that carry power and buy what they stock to start with. It is too expensive to buy powder over the Internet and pay the $20 shipping fee extra for explosives. For the longest time only thing I could get was Pyrodex, then they started carrying 777 pellets and then 777 loose. Other powers are hard to find where I live, but could be different where you live. So start with what is available locally, even Black Powder (Goex or Swiss), cause you gotta clean anyway after shooting. 777 is what I use now.
Chap Gleason