What kind of store could buy a lab coat on?

Am I obligated to buy a lab coat for my biology class only bank book in the school does not have a lab coat, except for size XXXL weighing 100 pounds thats not gonna help me .. I know that this is not the place to buy opnly one, but so far nobody can tell me where I can find one … So if you know can you please tell me …

any store that sells uniforms and supplies Medicall nursing but can not find it on Google Search or Ask Jeeves.

labcoat 2.0 Mission SJC