Amazon offers the Crucial Ballistix Sport LT 8GB PC4-19200 DDR4 PC RAM, model no. BLS8G4S240FSD, for $33.99. Coupon code "TWITCHCON20" cuts it to $27.19. Plus, Prime members receive free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $8.) That's the lowest total price we could find by $5 and the best deal we've seen for a single 8GB stick of PC4-19200 RAM. It features 16-16-16 timings. Deal ends October 7.
Update: It's out of stock but you can still buy it for this price for delivery when available.