until you accumilate the QUALITY brass to reload them yes its "expensive". this is a lax word. you dont shoot 100rnds of 50 cal in a outing(minus M2, etc). even full weekend matches are 60 shots.
instead of firing 1000rnds of .223 you fire 10-20 BMG. it all depends on what you like. just blasting rounds or blasting things to pieces.
yes everything is bigger with 50 bmg. yes there are special primers, presses, etc.
you can load and shoot surplus rounds(ball,api,api-t, S-T,etc) for about a buck a round depending on the size of the bulk purchase.
powder $0.50-$1.00 depending on powder used.
bullet $ 0.29 surplus or 2-4 bucks for match lathe turned ammo.
there is still no other feeling than to place 10 rnds in a 5-10"(inch) circle at 1000meters and still be able to penatrate most objects known.
they can be as pricey as you want them to be. there are deals out there but you have to look.
to each his own. but firing a 50 cal gives you and everyone around you grin from ear to ear.
HP & TQ are like SEX, you can never have enough!!!