i can tell you the cost for my 96 civic..
the original timing belt cost me 2400rs. the tensioner bearing cost me 900rs. i replaced all the other belts as well.. i think about 300 each.
the recommended milage for timing belt change is 100,000 km. i changed mine at 167,000kms. which is NOT recomended.
labor will be about 1k.
all the belts have to come off. then the main pulley will come off. then tappet cover loosen and timing cover out. loosen the tensioner bearing.. slip off the old belt. DONOT move the crank and cam even slightly while doing that. slip on the new belt in the same position..
fit the new tensioner bearing.. but keep it loose. turn the crank a few times to ensure the belt is seated and then tighten the tensioner bearing.. fit every thing back and all done.