Originally Posted by maeharasmuse

There used to be a system with logical codes for cash upgrades which I'm afraid is a pretty well guarded secret but the info goes around so I believe a bit of searching and/or a bit of patience might teach you how these codes were construed but it's been a while since I've last done this and it's not guaranteed and it's not always easy as the value sometimes is really exceptional besides I'm also not sure if these codes are still valid. .