Total AG Ratings: 258
I did what tha amish one said to do and got the artillery at wave 13. It did get kinda boring after obtaining artillery :(
Use the starting gun until you can buy the sniper. The sniper is OP and you can use it until you save up for the artillery strike. I had the artillery by wave 12, but be warned; the artillery is so powerful it will make the game boring.
Tips: I did this and it worked great; use the starting gun, and save up for an uzi. Once you have the uzi, save up for the Machine gun, and lastly save up for the striker. I came very close to losing a couple of times, but I won my first try, so I would do this method again. Also, while you are saving up, donate a little to your life each wave, and if you have less than 500 life at anytime, you should buy more life.