Furniture Bug
First save the game. Then take all the furniture from your restaurant(s) and put them int the moving van. Now load the game. You can now take the stuff you put into the van into a restaurant again. This is an easy way to make money.
Insurance Fraud
Take out liability insurance from the company that charges the most. Commit a crime and pay the fine. Claim on your insurance, and you should get a LOT of money.
Long term benifits
If you play the game for at least one year, the following will happen:
You will be able to edit the floor tiles.
If you play the game for at least two years, the following will happen:
Suppliers Out: 2nd Hand Studio
Suppliers In: Trend-setter Studio, New Age Videogames, Foil Coating, Restaurant Ratio Ltd.
If you play the game for at least three years, the following will happen:
Suppliers out: Marble floors.
Numbers for 'Ice Cream' dealers
Rome
4792922
2822724
3292746
Paris
7455342
3456789
4443267
London
7783493
7295254
7823552
New York
2854554
3224678
7345626
Berlin
2597546
8825314
Baltimore
7332562
3563287
Wien
2677435
7348178
Madrid
2764745
4854325
Chicago
5179239
5783917
Stockholm
2433143
Weapons dealing
To get real weapons when you dial up a joke store using the terminal, ask for ice cream. The various flavors are actually weapons:
Lemon: Bombs
Vanilla: Flame throwers
Strawberry: Bazookas
Chocolate: Poison
Better Underworld rank
Use a character with a lot of money. Phone the Joke Article Shop. Buy 1 lemon flavor ice-cream, then sell it. Repeat this approximately 15 times to get a better rank.
Buy a lot of "Ice Cream" and that will boost you, but make sure you use your "Ice Cream". After you get the "It's 9 p.m. and all the restaurants are closing" message, click on another person's pizza place. You will get an option to use any "Ice Cream" you may have. Once you use it, keep doing so and your status will keep increasing.