the DoubleTap seems relatively cost effective
Sportsmansguide sells the Federal 180 gn Castcore; $25 for a box of 20, that's $1.25/round
DoubleTap direct is selling 200gn Castcore; $40 for a box of 50, that's $0.80/round
not trying to be an advertisement for DoubleTap, I just thought the stuff worked pretty good for me, good controllability, no extraction problems, etc
I usually practice with lighter stuff at a range, this is really just to be carried in a hiking gun