Multimeters needed.
I often get told by parents to let them know what we need. Grapevine parents are VERY generous!
Well, we need good, solid, simple multimeters. (Actually, would a great present for your PreAP kid!)
General Specifications: Digital; Reads Current, Resistance, Voltage (Amps, Ohms, Volts); should be between $20 and $30.
Here are a couple of specific examples:
From Home Depot: GE 17 Range 6 Function Multimeter (at Walmart, too). I really do like the Sears ones better, though.
Sears has several good ones:
Item# 03482141000 Model 82141 - 8 Function, 20 Range Multimeter