I've been on the same quest as the OP, and after searching high and low, the CZ 527 carbine was what I came up with. It really does seem like the best option here.
What purpose do you need it to serve? I need a new centerfire mainly for target plinking, with the possibility of harvesting small game. A Saiga in .223 would have been my first option for the price, but good luck ever finding one in this market. Kel-Tec's SU-16 is cheap as well, but again its a matter of finding one.
So if a tactical-ish semiauto plinker is out of the picture, I suppose you might as well get a nice accuracte bolt rifle, like the CZ The Remington 700 SPS Tactical is a close second second choice, but I prefer iron sights for most shooting practice. The cheaper bolts don't appeal to me, especially if they don't come with iron sights.
The other option is buying a single-shot NEF Handi-rifle or the like, those are cheap and many of them have iron sights. It's cheap, .223, and available still.
Good luck with your quest, I'm in the same boat, and will probably pick up the CZ 527. It's just going to have to wait a few weeks until I take care of some other expenses, so I hope there are some left. Everything that is .223 is in short supply... even brass! I may say heck with it and get a .257 Roberts...