The size is small -- are you thinking of putting them together to make a pastry rollout spot? They would have to be seamed.

I really don't know what remnant prices tend to be, but based on the price of my slab the material cost would be about $25 each. A fancier marble could be two or three times that, a grayer or lesser might be less ($20?). You could say it should be less as a remnant or more if it were considered a usable pastry or candy making slab. It is small for my thinking, so I wouldn't go higher. That would be just a raw, cut piece. If these have been fabricated, that would add to the cost. You can pay 10-15$ a foot for a simple treatment and more for something fancier.

Actually, these are two slabs from a coffee table, I found on CL (LOL) and I don't know if they can be used in the kitchen or not...but they might work well on each side of my range. They are narrow areas, but I have more countertop to one side, which I am replacing with another material (it is part of an L). Probably not a great idea...but I thought I would ask :)

3/4 inch thickness is fine. Can't see why you couldn't use them