At the start of the game, if your IQ is 15 or above, you can enter the transport in the registry department where you start. Type "LETSGO" and "01" to use the transporter, then "LETSGO" and "00" to return. With the 15 starting IQ allowing you more initial agility, you can fix broken items easily.
Easy credit boost
You can goad the East Zone checker robot into the stairwell behind the FA74 passcode Spider gives you, in the Novue Apartments. There, attack it, search it for credits, climb down the stairs, heal--or even buy new items--and come back up. It will regenerate after about 50 moves and be waiting for you. Other enemies cannot reach you there.