At this point all you can do is cancel the bids if you feel they're not serious. In the future you can post in your item description that you don't accept bids from buyers with less than 5 feed backs.
In my experience the hand held vacuums aren't very good. Their suction isn't strong and unless they have a bag you can empty or change the filter that's built in gets so dirty you wind up just blowing more dust around the room.
Good vacuums (like Dysons) are super expensive. If you can find...
Check your cell phone. Mine has a timer on it under the "my stuff" on your menu, then go to "tools" and scroll through that to see if there's a timer on it.
If no one offers you a tour, ask someone in the principals office. They could probably arrange for you to have another student show you around. If you're going to be a freshman, there's probably a planned orientation.