4 inch solid blocks are about €1 each.if building in 4 inch solids you'll need a 300x300mm foundation x 6m long costing about €220-€360 concrete delivered.foundation dug out 2 lads 2 days is about 240. Motor will be 2 bags about €120.labour 2 lads x €125 per day allow 3 days and a skip coasting about €250.
You'd be between €1800-€2500.
Capping would add another 150-200.
You can keep costs down a lot by taking the wall down yourself,digging foundation,loading blocks,filling skips etc.some people buy top soil so bag it up or some of it.
We only got a wall done our self and would gladly recommend them if your based in Dublin.