Work in the United States?

I am a legal permanent resident of the United States. I was born in Colombia and came to the USA when I was 5. I will be turning 17 next month and would love to begin to work. My Social Security Card says I can only work with the valid authorization of immigration. Has anybody gone through this process before and can tell me what to expect and what are the steps??? And how much are the fees and about how long is the waiting process until approved??