Looks to be about 1.5m on each side (based on 1.8m - 30cm).
Volume of the cube:
1.5 * 1.5 * 1.5 = 3.375m³
Density of tungsten = 19,450kg/m³
Mass of cube:
3.375m³ * 19,450kg/m³ = 65,643.75kg = 65.64375 metric ton
Price of tungsten: 6,672.78 USD/metric ton.
(Tried to find what I thought was a reputable price)
Price of the cube: 65.64375 mt * 6,672.78usd/mt = 438,026.30usd
Hope that's reasonable