Rimfires are where it's at in the cost per use generated category.
It's a toss up for me :
'48 BRNO Model 1 .22LR w/tuned trigger
'51 BRNO Model 3 .22LR (HB)
bought the Heavy Barrel Model 3 for parts, but I've since put many bricks through them both !
Both are shooters, and great value !