Tools

  * CE - CE -Cheat Engine 5.5 [Link1]
  * FP10 - Flash Player 10 [Link1]
  * Firefox 3.5

Steps:

  1. Go to Happy Pets 
  2. Open Cheat Engine, Process Firefox.exe(Browser)
  3. Tick (Hex,Array of bytes, ASROM)
  4. Scan "85C00F848B0000008B48088B49548945", 2 address should returned
  5. Right click the 2nd address and click "Disassemble memory region"
  6. Now , Find line "test eax, eax" and change it to "test eax,ecx"
  7. Now click on your piggy bank or visit a friend and click on his piggy bank
  8. You will notice that the coins in the piggy bank will not disappear but your amount of coins keep increasing
  9. You can use a mouse recorder to automate the clicking
  10. Once you satisfied, shift out some furniture and wait for a while for the game to auto save.
  11. Just refresh the game and coins should still remain