use drywall method...aka partition for the store, close up the staircase riser with matching timber plank, less than 3k i guess

kayu + papan rm500.
besi rm 500
labour for form work & besi 2 worker x 4 day x rm70/day = 560
concrete 2m3 + labour = 600
cement, sand,tiles + labour = 2000
total 4160

still ada untung

read carefully, concrete casting & tiling work item was separate out..

for formwork + rebar work, 2 worker 4 day already more than enough lor

this is exactly what i sugguest @ post #4

if use ply wood, do undercoat it with solvent base under coat paint 1st, then u can paint it over with normal wall paint without any problem later