Well, how do you open the console in Ren'Py?
If you open UnRen and use option 3, you get the ability to open the Console AND the Developer.
To open the Console, you press Shift + o. Type out the console command you want to change and press 'Enter.' You can scroll thru previous inputs with the arrow keys. This is helpful if you don't feel like typing out "give me more money!" every time.
If you open the Developer (Shift + d) and chose "Variable Viewer," you typically get to see a list of things you can change. Here you can see what each variable is set at and what to type in order to change it. The front page of this thread tells you all the codes you'll need, but the "Variable Viewer" is useful for other not-so-helpful games. The Developer also has the option to open the Console. I wouldn't suggest using anything else in the Developer, unless you know what you're doing.