The developers at PopCap poured hundreds of hours into the physics, the level design, and the hypnotic soundtrack of Zuma Deluxe. They deserve the $4.99. More importantly, you deserve a safe, hassle-free experience. You deserve to jump into the Temple of Zukulkan without worrying about spyware corrupting your hard drive.
Technically inclined users have found ways to disable the timer in the trial version using memory editors. However, this requires technical skill and risks instability. It is much easier to just pay the five dollars.
But here is the reality check you need before pasting that random string of letters and numbers into an installer: The gaming landscape has changed, and so have your legal options for playing this tile-matching masterpiece.