You're kinda limited....
16 years old and no skills, no education, no expereince, no special training or skills, and only want to work weekends.....super market and retails sales are about it. Telemarketing is an absolute pain. People like me yelling at you and calling you names and disparaging your family tree because you called when I was trying to 1) eat dinner, 2) watch TV, 3) read undisturbed, 4) answering nature's call, 5) spending some husband/wife time, if you know what I mean...
While the money is a nice way to support your habit, I'd say retail sales in a sport/activity you like may be best. You get to learn a lot about that sport, you get to play with the stuff, get employee discounts, and learn about selling. Remember that your job is not to stand around bs-ing and chekcing out the girls, your job is to help move merchandise and sell to the customer. And that means learning how to communicate, how to speak and communicate in complete sentences and not like, you know, like, this is you, know, so sick, like you know...you need to learn the product to knowledgably describe it and sell it to the customer. Remember that you have to sell the product before you can sell the product. You might learn something else....about discipline, getting to work on time, getting to work when it's raining or when your girlfriend calls, or when you just don't feel like it, or to do the job right, or that every dollar earned is hard work and when you see how much Uncle Sam takes out to feed ever moocher around, you'll start hating these damned liberal tax and spenders.....you might learn more stuff like learning not to cuss out a PITA customer but to learn to solve problems and swallow guff because that's the real world when you need to work and put food on the table and you don't have the luxury of telling the boss/customer to stuff that snowboard where teh sun don't shine.....
Perhaps the best job is working at some shitty job where you really hate the world. I did enough of that and I know the older ones here have all worked at shitty jobs where you hated going to work everyday....why? we got where we are today because we do not ever want to work at that shitty work ever again...and either......great lessons is life to be had if you look for it...
sorry to give you some facts of life, but you're never too young to learn what the real world is about.