I, for some reason, do not have any of the white stones needed to place my sign. I have a cracked red orb to banish phantoms, though. Do you get one at a certain part of the story? Do I buy it...?

Thanks.

I have a small white soapstone and a large white soapstone. I came across both through my travels, did not need to buy one. There's a small white soapstone on the floor above the bonfire in Cardinal Tower. I don't recall where I got the Large White soapstone. Small whites are active for a short time only, so it's best used before a boss arena.

Pate gives you the White Soapstone - just before the first boss.

Yup, Pate hadn't given me the stone yet. I thought I had talked to him completely, but nope - one more important bit to give. That's a Souls game for you.

After that instance, Pate will relocate to Hunters Cove I believe. I may be mistaken with the area name. You could try to get it still?