Hello techs out there what's the price to replace the capacitor and install hard start which is another small device attached to the unit to run you air condition unit ?

In Bangladesh... or Malibu Beach? And on what exactly... its impossible to answer this question as presented with the information presented.

You should contact three contractors in your area ans solicit bids.

Depends on where you live. $150-200 would be a guess. Service call, hard start kit is about $30 and cap is another $10.