AI am looking for good places to get chocolate for ganush for my cakes and do you charge more for a cake with then one with butter cream

you want to buy as high quality of chocolate that your market will bear to pay.  I think that you really can tell the difference.  In the grocery store, that may be getting the Extra Dark Giradhelli (sp?) REAL chocolate chips instead of the chocolate baking morsels (not real chocolate).  Or buying your chocolate in bulk in large baking bars (Trader Joes has nice Pound Plus bars). Or you may want to go through Restaurant Depot or an online order.  Because ganache is just two or three ingredients, you can't hide a poorer quality chocolate. As with all ingredients, you have to charge more to cover your expenses. So if using a nice chocolate costs out higher than your usual buttercream ingredients, then you could charge a premium for the premium frosting.