For an optimum in wave run-up reduction, maybe the cheapest way is to place huge layers of ruble stone as a shore revetment.
Such revetment will reduce the wave run-up with 50%.
The big disadvantage of these ruble stone slopes is that they need a lot of space in order to function as a stable and safe revetment. The gradient of the slope starts at a minimum of 1:4 all the way up to a flat surface (beach as wave reduction). In urban areas these slopes are no option. Also the access on rumble stone revetments for maintenance is very difficult.
Hillblock: steep slope and accessible for maintanance
Hillblocks can reduce the wave-run up with at least 30% on a slope that starts with a gradient from 1:2 or flatter.
The usage of Hillblocks are ideal for populated or urban areas where there's a lack of space or expansion capacity.
An other advantage of the blocks is the flat top, so vehicles can access the revetment easily for maintenance.
On the video you can see a pick up truck and a midi digger of 8 kiloton.
With of the band 450 mm
Ground Pressure 35 kPa (0.36 kgf/cm2)
Fraction force 60.4 kN (6 160 kgf)
The forces were applied to a 20 cm Hillblock (Base and Slim model)