How low cost is low cost?
Raspberry Pi, $35
Pros
Designed with students in mind
Can easily be restored using NOOBS SD card
Cons
Not as fast as those fancy Apple computers
ODROID C1
Banana Pi
Beagle Board
Radxa Rock
Arduino
Old cell phone
Intel Compute Stick
Intel Edison
Intel Galileo
Chromebox
By Manufacturer
Atmel
Freescale
Microchip
NXP: LPC1788
ST: STM32F207, STM32F401, Nucleo-F401RE $10.32, STM32F103C8T6 $4.66, $6.28, STM32F103RBT6 $9.85
TI: EK-TM4C123GXL $12.99