Sanitaire TRADITION Upright Vacuum SC886F. shake out bag and 50-foot cord. Current: 7 A; Tank Capacity: 18 qt; Color(s): Red; Cleaning Path: 12". Global Product Type: Upright Vacuum Cleaners. Learn more about theTRADITION Upright Vacuum.
Inexpensive,very good at what it does, and easy to maintain.
I've been a custodian for about 25 years. The School district I work for was using the red bag vacuums exclusively, when I started.
I don't believe there is a better machine for maintaining carpeted surfaces (esp if you opt for the 4 brush beater bar). Quite a few people use a back pack vacuum, but they cost about $500, are not easily maintained, and they do not clean as well as a stand up with beater bar. Not to mention I'm 6' 4" and it doesn't fit me well at all, then there's the hose and giant wand (which is made way too cheap for the use it gets). And you shake out the bag, or you can get a bag in a bag if you are so inclined.
You can get a magnetic strip to catch paper clips and such, If you do this, do not just atachi it with wood/ dry wall screws, drill through the tabs and the front of the base, and use a 1/4 inch machine screw with a nylock nut and washers.