GPU prices dropped considerably throughout the month of March due to a series of factors that include: Amazon and Newegg refreshing their supplies more often, rumors about a possible July launch of the GTX 11 series and a late 2018 AMD Navi launch, plus Bitmain's announcement of the E3 Ethereum ASIC that could spell the end of GPU-based cryptomining.
https://www.notebookcheck.net/AMD-Nvidia-GPU-prices-are-down-25-in-March-supply-is-catching-up.296424.0.html