How much should I charge for these?

sell them to an early 20s indie boy and tell him that they're "soul squares" QHICH ABSORB BAD ENERGY AND EMIT GOOD VIBES AFTERWARDS. by low sell high.

They're not decorative so I don't see anyone buying them except for the purpose of using them for tiles. 

Not much..looks weak and cheap

From the photo they look just like like tiles.  Like floor or bath tiles.  Not sure why anyone would buy them. Perhaps after you have put art work on them.

If they're made of fired mud, Mexican kitchen tiles but need artwork. I can't spell porceline. Price, what the market will bear.

Nothing. If I wanted random samples to hang on my wall, I would get them sent them from a supplier.