Actually 9mm is pretty cheap. I buy mine at Chin...err Wal-Mart, (Winchester white box) 100rds for $12.
But for some reason most gun stores try and sell 9mm for around $10 for 50. I just laugh and go to Wally World.
.45's are $20 for a box of 100.
But your right about the .22's, you can't beat 500 for $10.
100 rounds for $12 isn't bad.
For a beginner, though, that Ruger 22 is just a great pistol for learning to shoot. It's accurate to a fault. Any in the line of Mark II or III with a bull barrel is a great buy.