Recommendation please: Small inexpensive DAC for smart phone to receiver


I have a late '80s McIntosh mac4280 stereo receiver and have been using the headphone output of my Android phone connected to the Aux input of the receiver. 

I'd like to install a small inexpensive USB DAC between the phone an receiver to improve the sound quality.

I went to eBay and Amazon and was overwhelmed with all the Dacs, many from China, some with headphone output only, others with rca outputs which I need. I don't know where to begin looking. I'd like to keep it around $100 - $150 for a first phone Dac for my Android phone to stereo receiver.

What do you recommend?
mjcmt
Look at Audioquest, Oppo, Fiio, Ifi. 

Most of these are battery operated headphone amp/Dacs.  Most also have a line output capability. The Audioquests will need a cable adapter.   

Love my Oppo HA-2 purchased here for $250.  
As per dbtom2, check out the new Dragonfly Black (v1.5) or Red from Audioquest.  They were developed specifically to work with phones.  

ALSO, check out Schiit Modi 2.

The Black v1.5 and Modi2 are in your price range and should do what you want.  

I have a question, can I use any usb DAC with my smartphone with the proper adaptor cable that will allow me to plug my Android phone into the DAC.