Personally i would look for a new device! as mentioned above by another user - these models are renowned for issues!
A few notes:
A second hard refurb board can be found online from anywhere between $200-400+ , in contrast you can get a second hand '''Retina MacBook 2015''' for around $500-600+ on auction.
After looking into the above two options another $800 seems a little steep, i would put that money towards a new device and sell the Macbook as spare and repairs working screen for $200+ on ebay or somewhere similar