Fred, you don't need to go to Bulgaria to buy it, any good fireplace shop or even the big box hardware stores carry the extruded ceramic stone for indoor fireplaces. Might save you an airline ticket. As for pricing, some of those big box stores offer samples of exterior facing fake rock for free, or at low cost which can be used the same way. Here's another old model Railroaders trick (I know you and I are both old model Railroaders-- emphasis on old for me--I can't speak for you!)--you can make a latex mold of this material and cast it in hydrocal (plaster for you non-model RRs out there), so that you can have as many rocks as you need. Model Railroaders frequently use one mold to make 4-5 rock faces by alternating the positions of the casts. On the other hand, this material can be carved itself once heated, but it would be more expensive to buy it that way if you needed a lot of rock (as model Railroaders typically do).