Everything in the shop costs $1. After the first shot you'll be able to get everything. No need of other hacks since it will take the fun out of the game.
Toss The Turtle Hacked
Fire the Turtle from your cannon as far as you can get him.
Visit the shop after each time your tutrle stops to buy upgrades and as your playing this hacked version you can buy everything in the shop for just $1.