Are cover letters a little too much when applying for a part-time job? (high school student)?

I'm not sure if they are hiring right now, but i want to be called for at least ONE interview. rather than passing my interview around at every single store at the mall, should I make cover letters for a few places that I really want to work at and enclose my resume with the letter? If you are an employer, would you think that the applicant is being a suck up, or is showing determination?