Singles: Flirt Up Your Life Cheats

Open "config" file in the game folder. Search for "game.dat", and open with Notepad/ Wordpad.
Find:
>moneystarttutorial: 2000
>moneystartflat: 2000
>moneystartloft: 15000
>moneystartcottage: 50000
Change the numbers (whichever you prefer) to 999999999. This will be the amount of money you'll have when you start the game.
-->This process involves modifying the game file, so please make a copy of "game.dat" first.

Note: This procedure involves editing a game file;
create a backup copy of the file before proceeding. Use a text
editor to edit the "savegame?.dat" (where ?
is the number for the saved game) file in the "savegame"
directory in the game folder. Search for the word "money"
in the file and change the number behind it to "999999".
Note: This procedure involves editing a game file; create a backup
copy of the file before proceeding. Use a text editor to edit
the "game.cfg" file int the "singlesconfig"
folder. Search for the word "money" in the file and
change its value to "999999". There are several money
entries in the file; all of them should be changed. This will
now allow you to start the game with that amount of money.
Trainer: +1 by DEViOUS
Trainer: +3 by ASX
Trainer: +5 by Deviance

Backup the file you are about to edit before proceeding. Go to your savegame folder, and open savegame?.dat (where ? is the number for the saved game that you want to edit) in notepad.

Do a word search for 'money' (press Ctl-F and look for 'money'), and change the number beside it to 999999. Now save the file and run the game and you should have lots of money!

I'm not sure which versions this works on but others have reported success.

Go into the building mode and build a long wall. Delete the wall and build it a second time. This time the wall won't cost anything and if you delete it now you'll get the money that it would have cost you to build it back. Repeat this a few times until you have all the money you need.