two years ago my friend said you can get a used samson, bridgestone, baramon, bomber pro, you name it, for $50-100 easy. now they go for about $500-6. nagas and 3rensho's are up to $900 on yahoo auction. everybody wants a piste bike in japan now. and prices keep going up every week. there aren't really any "deals" anymore except on parts.
with that said, my friend was out in the countryside and came across a mom n' pops bike shop. just out of curiosity he went in to see what they had. asked if they had any piste frames and was shown to a dusty old garage. he dug thru stacks of frames and found two 3renshos and a vivalo.
owner sold it to him for $50. all three frames together.
happy hunting.