I love my 550, and load and shoot a bit of .45acp.
Even with the handloading, I am still shooting a lot of .22 LR.
At my best, I can load .45acp for .14/round.
I can buy .22LR for .03/round.
So I can shoot five rounds of .22LR for each round of .45, and that ignores the time and effort required to handload.
I try to shoot once a week, and typically shoot 100 rounds of .22LR and 50 rounds of .45acp. Unless it Steel Challenge night, when I shoot ~100 rounds of .45 (and lose almost all of my brass)
By my math, shooting 1500 rounds of .22LR (about 15 weeks) paid for my $200 MkII a long time ago.
I'm not trying to spend your money for you, but a .22LR pistol is an extremely cost-effective way to shoot frequently and develop/maintain proficiency.