What is the best detox to pass a drug test and do they test for it?

Ok...so I'll be 17 in a few days and I'm trying to get a job. Before you judge me, I'm a good student with all A's and B's and I'm very involved with school activities. I smoked weed yesterday. It's not something I do ALL the time, but just every now and then. I was wondering what the best detox (that's affordable) to get (besides not smoking, that's a given) and do they test for it in your system? If so, how long? If your just answering to tell me that I'm waisting my life by doing 'drugs', please go answer someone else's question and leave your hate there.