<human>: Hey reddit, as the title says, I'm in a bit of a pickle. (Throwaway cause many of my friends and coworkers know my main account)

I am 16 years old. I started working at a local Chik-fil-a fast food restaurant as soon as I was able to work for the summer. (Chik-fil-a is one of the only local places that will hire 14-15 year olds around here). So first day of summer comes around freshman year, I head in and end up leaving with a job. As it was my first job and I was still very young to be working, I was glad to accept my short hours at bare minimum wage. 

However, now I am a junior in highschool. For my one year anniversary of working, I was excepting a raise. But apparently they had changed their terms recently and instead I was awarded a $20 in-store coupon. I was hoping for a raise, but nobody told me about any type of pay raise or mentioned it since. Is this normal? I've worked another half a year or so since, and I've been commended to my managers by customers, complimented by management, and even got an honorable mention for stellar achievement in a newsletter sent to the entire local franchise. I later did some searching after hearing someone say they had gotten a raise. Apparently, the average wage for my position is [over a dollar] ( what I'm currently being paid. 

So my question is, how should I go about asking for a raise? I'm working, attending highschool, and saving for a car. How much should I ask for? Any suggestions for an approach?

Provide a brief overview of the text.
<bot>: Been working for a bit over a year and a half, got a $20 coupon instead of a raise at 1 year. Apparently getting [underpaid] Want suggestions on how to ask for a raise.