The .223 being notably cheaper is kinda a myth unless you are willing to feed it poor performing ammo. When it comes to hunting grade ammo it's not much if any cheaper than the other .224 caliber centerfires. Personally when it comes to .224 centerfires my favorite is the .22-250.
You'll find all sorts of arguments about the ethics of using .224 centerfires on deer. Some will even argue against the 6mm's for that matter. I'd just as soon not visit all that again so I'll just say for varmints, predators and deer I'll take a .243. As a matter of fact after handfuls of centerfires the one bolt action I currently have is in that cartridge.
You don't mention where you live but I'll agree with all the post, both for and against, concerning the .30-30. It's far from a great prairie dog gun but a good .30-30 lever gun will kill anything in the lower 48 and has a big fun factor at the range.