I was lucky in that I bought a box of Squats and some vehicles waaaaaay back in the 'Epic Space Marine' days. Then last year I scavenged a few bargains off eBay while the AUD was going strong.
You don't really need a lot for a few thousand points of FWC forces, and there's not many constraints that make you buy three of everything and so on.
I've picked up some other stuff off eBay, and added that to some bits I already had ... so my poor Squats are going to find themselves a bit set-upon as a neighbouring stronghold falls to a Chaos Cult, and the feral Orks in the badlands suddenly get organised. But Imperial assistance will be on the way! Although that might get messy as well...
Still a fair bit of painting required before that all comes to fruition. I think the Ork problem may be the first to emerge.