By what you have described it sounds like you have come across some Indian Attar. More then likely synthetic. From the prices you have described they are probably not natural or at least very little. Most of the purist forms of essential oils can be found easily on the internet or certain specialty shops here in the west. For instance the musk you have described, Agarscents sells the purist form of Musk I have ever smelled as He claims it is pure, and it goes for around $600 US. But I myself have seen and sold many attars called musk for the same price you have mentioned but they were for sure synthetic or vegetable based.