Just saw a video about finding a 2nd hand server for the budget around 5000rmb (usd to rmb is around 6.8rmb for 1 usd, data from google)
Hardware spec on the screenshot(original video link, in Chinese language):
Dell R730, E5-2680v4 * 2, ddr4 ram 16G * 8, 6TB SAS drive * 5, H730p card, PSU...