I got it to work with the cheat engine the way to make it work is to drop your money to extremly low numbers.. then just sell like a corpse at a time since the value is so low it's easier for the system to lock on. I got my money !
There's already a table for XCOM on the CE forums. It's not...all that useful, and good lord do you really have to know what you're doing to use it, but it's there. But yes, those forums are the place to watch if you're interested in using CE at all.
Money works the same way as any other editor. Just put in the amount you have in "first scan". Then sell some stuff and enter the new amount in "second scan". Just don't put too much money in, or it sets you to a negative value because you go over the max value. Just go around 300k credits.