Newegg has the Rosewill R218-P-BK-450W Mid Tower w/ 450W PSU for $40 with free shipping. Features four 5.25" external drive bays, one 120mm case fan, and a 450W power supply.
Case would work for a cheap office build, but the PSU is best avoided so as Casecutter suggested, you can get something better for same total cost once you factor in replacing the PSU before it fries something... though that Cooler Master is a bit flashy for an office build.
Man, IDK the PSU seem weak and the aesthetic are fugly.
Check this COOLER MASTER Elite 430 RC-430-KWN1, no PSU but it $40 -AR$10 w/FS. Black interior, Toolless, bottom mout PSU, a window, blue LED fan worth a look!
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119227
http://benchmarkreviews.com/index.php?option=com_content&task=view&id=574&Itemid=61
http://www.legitreviews.com/article/1401/1/
Case would work for a cheap office build, but the PSU is best avoided so as Casecutter suggested, you can get something better for same total cost once you factor in replacing the PSU before it fries something... though that Cooler Master is a bit flashy for an office build.