Device
Made By
Source(s)
Price/Qty
Features
PIC12F675
Microchip
Digikey
$2.08/1
$1.33/25
6 I/O, 4 A/D
great for small projects.
PIC16F819
Microchip
Digikey
$3.70/1
$2.10/25
16 I/O, 5 A/D, PWM, etc.
for lots of projects
LTC4627
Fairchild
Mouser
$2.52/1
$2.20/10
4 digit x 7 segment LED
Multiplexed
FAN8200
Fairchild Newark
$0.64/1
$0.57/25
Dual H-Bridge 2.4 - 7 volts
600 ma, great motor driver
TC4426
Microchip
Digikey
$1.50/1
$0.95/25
Single H-Bridge 5 volt logic,
22 volt output, 1 amp
RCT-433-AS
Radiotronix
Mouser $3.99/1
433 Mhz Transmitter
RCT-433-RP
Radiotronix
Mouser $4.99/1
433 Mhz Receiver
TSAL-6200
Vishay
Mouser $0.21/1
IR LED  940nm
TSOP-4838
Vishay Mouser $1.08/1
IR Reciever 940nm 38khz 
(100 LED's)
(who knows)
Circuit Specialists
$1.50/100
3 or 5 mm in Red or Green
TL072
NJR
Mouser $0.32/1
13 v/us dual jfet opamp
IRF644N
IR
Digikey $1.45/1
$0.84/10
MOSFET/HEXF NCH
250V 14A TO220AB
LM324N
Fairchild Mouser $0.33/1
Quad OpAmp DIP-14
LM2931AZ
Fairchild Mouser $0.24/1
5 Volt LDO regulator