Creosote-treated wood/ties?

Anyone know where I can get some?? Preferably 4"x4" in either a 6- or 8-foot length? Don't really want reclaimed RR ties if I can avoid it given they're a PIA to find without some rot/splits and aren't always even (need a somewhat tight stack). Would go with pre-stained pressure-treated lumber too. Last choice (which I'd prefer to avoid, but I know beggars can't be choosers) is the HD aisle and a gallon of stain, I guess. TIA for any ideas.

I used 4x 6 in 8 ft lengths to build a raised bed for veggies. Didn't want creosote for that. Got them at HD. Pretty sure they also had 4" x 4" then. Awkward as hell to transport but I seem to remember you have a teenage assistant to work with.

Thanks. I have better: a contractor. Though yes I do have one, and otherwise he'd be helping, that's for sure.

Creosote is somewhat important as these are for retaining about a ton of cobble and earth, unlike a veggie bed where you want the worms and bugs in there keeping things loose. But it's not like they're supporting a building so yes, you're right HD isn't the worst thing.