Here is what I would get with $50 and starting from completely nothing and none of the students had parents with anything.
Dollar Store (Dollar Tree, etc)
Allen Wrench Set SAE = $1 (I actually have been buying a bunch of these recently, I'd probably end up getting two of them for the team)
Vice Grips = $1
Home Depot
Hack Saw -
$4 at Home Depot
Harbor Freight (for the free stuff watch for an Ad, they're free about every other month or so, SnipSnap is a smartphone app that always has the latest Harbor Freight Ads)
Tape Measure - Free
Multimeter - Free
Flashlight - Free
File Set -
$7
Target
Corded Drill -
$18 at Target
Walmart
Socket and Bit Set -
$9 or something similar
Drill Bit Set -
$13
That's pretty close to the $50 and you could scale down some of the stuff.