Fetal heartbeat Doppler

Vanessa
So I was on fb and seen a Doppler for sale. I'm planning on purchasing it tomorrow. 
Anyway my question is, who has used one? Like personally at home, often...
How was your experience?
My dr asked me not to get one because it would be a waste of money... But I miscarried at 20 weeks last pregnancy and my body didn't show any signs, I only knew when a scan revealed no heart beat. 
So I plan to use it as directed obviously, and I see where exactly my dr puts her scan when she hears baby heartbeat so I should be good yeah?