dont think it cost RM20-30 depends what car and how hard to unlock it...
but getting a lock smith is the best way rather than smash the window or go to proton to duplicate the keys IF the key is in your car

once my key is lock inside my satria with engine start  
i wait for 30min to wait the locksmith comes but only took him 1-3 min to open my door

i never lock my inspira key in the car

the satria's key is lock due to some brake problem
its a long story...
i drove my car to work, after work i 1 2 unlock the car using remote somehow no response
after check due to no batt borrow car from colleague then buy and replace the batt
start car success, left the car when the car is start close the door went to pick up something in the office
wtf the door lock check what happen looks like the brake is jam....
some of the remote system will lock the door when press the brake right?
after that then i notice my batt died due to the brake light kept on when i working