Go to the "Articles - Charts - Links" section of the fourum. Click on "links," then "powder" for a pretty comprehensive list of blackpowder suppliers and suppliers of the subs.
I tried pyrodex shortly after is first came out, years ago. My groups went from about a coupla inches at 50 yards, off the bench, to barely staying on the paper. I could never get any accuracy with Pyrodex, so I went back to black and never looked back.
Some folks get decent accuracy with the subs, and ya gotta shoot what is available, however, I would try real black powder for a comparison to whatever is readily available in your area.
There are several suppliers who will ship less than five pounds of powder, so read through their sites, listed in the links section, to see what they offer.
IMHO, all of the black powders offered today are good. And you may find the price of black less expenisve than the subs...or may not, depending on what quantity you buy.
Good luck
J.D.