Just type "petchko online save editor" in google, click on first result it gives you, and than go on "upload file". There you put your save (it's in documents,appdata,local,renpy folder or something like that) and it will give you list of all items and variables. Money should be close to top of the list. Type amount you wish, save, download and replace old save with new one.
Now, you can modify pretty much anything you want, for example, relationship points etc, but that's not advised cause it can break your game. Money is safe to add, I've done it million times, never had any problems. If you want to mess with other stuff, than backup your saves.
