I'm having trouble finding anything in cold-rolled steel plate, especially in that size. Ideally, I'd like it with both sides flat ground/precision ground, as I'm using it to mount a mill to for leveling and vibration mitigation.

Anyone out there have anything like that available? I'm not looking to spend much, but I'm interested in any quotes a member can provide.

Let's put it this way- McMaster-Carr has what I want- at a 1000% markup, around 580$. This is plain steel we're talking. That's ridiculous.