[SpecterH]

You have three options:

(1) Stick it out and work there;
(2) Try it out for a little bit, and then quit;
(3) Tell the manager that you are no longer interested prior to starting your job

To me, it seems like you really want to select the third option, but are worried about the repercussions of your decision; mainly, how it'll look to other people. I'd talk to your friend about it, and explain the situation. If he's a good friend, he'll understand how you feel, and work with you to try to mitigate any damage that was done. As for other people on Facebook, who cares about what they think? I guarantee that most of them will probably forget about this job in a week or so (except those who are close to you). And, for those who are close to you, surely they will understand why you didn't end up pursuing the opportunity.

Ultimately, you need to do what you feel is best for you. If you don't want to work at Radio Shack, you're probably not going to be an excellent employee. Why would you risk enduring bad reviews from your manager, due to a lack of performance - for whatever reason - simply because you've already told people that you're working there? People change their minds all the time; it's a natural part of life. Besides, this is only a part-time job; it's really not a big deal. You'll probably never work at Radio Shack again, so why does it even matter?

I can see how you may be worried about dealing with your friend, who has gone out of his way to help you get a job there. Be honest with him, and explain that you won't enjoy the job/don't have time/any other reason. Like I said, if he's a true friend, he'll understand. Besides, I'm sure they can just hire one of the other applicants who interviewed with you. Trust me, retail stores are in no shortage of hiring part-time workers. I really wouldn't think too much into it, if I were you.

I'm not sure how long your school year goes but, perhaps another alternative is to ask them if you can post-pone your start date until after you finish your school year. This way, you'll have a lot more time on your hands to potentially work both jobs. You can gauge whether or not you enjoy the job after a month or so and, if you don't like it, the opportunity to exit still exists.

Ultimately, do what you feel is best for you - and don't worry about what everyone else says. You're the one who will be working in the job, so it's your decision.