So, i'm not sure if this is wellknown, or if this has been mentioned before. If it has, ignore me!

If you want a fallback pool of creds, do this. When you start a game, play for about thirty minutes, then save and exit. Go to the load game thing, and load the game u where just in. INstead of loading your civ, load a different one. When the game opens, construct revenue earning stuff for the other civ, then again save and exit. This time, open up your civ, and play. When ever you need a lot of creds fast, save and exit, then reopen it under the other civ you had used. By this time, they'd have built nothing, and you can make them give all their creds to ur civ.

I've done it a few times, and it really works well.