I'm watching the 54r brass as well.
New Lapua 7.62x53 brass is $125/100 - Hirsch, Terso, Prophet River carries them and in stock.
New PPU brass is about $85/100 - Tradeex and Rusty Wood carries them but are always out of stock.
SFRC sells S&B and PPU brass cased ammo for ~$30/20.
Gun shows, you will find good price there. I saw a bunch of them at a show earlier this year. They were Lapua 7.62x53 brass, once fired presumably, sells for really cheap. And no one was interested in them! I didn't know better at the time thought they were different than 54R and didn't buy them. Oh well.