Fund raising and things you can do to earn money.?

Hi guys! I am wanting to go to this camp this summer. The cost is $400 though. I was wondering you any of you had any ideas how I could go around selling stuff and what I could sell. Right now, i am selling candy and mulch but i dont know how well that's going to turn out for me, so i was wanting to take up any of ya'lls options. I thought of being a dog walker since its getting warmer out where i live..but im allergic to dogs and cats. So, PLEASE let me know if you have any ideas. Thanks! :)