The unrighteous penny corrupts the righteous pound.
More German Proverbs:
There is nothing so bad but may be of some use.German
Early to bed and early to rise, makes a man healthy, wealthy, and wise.
German
Old churches have dark windows.
German
Not too little, not too much.
German
Running and buying don't go together -- running and selling do.
German
Many small make a great.
German