I purchase these little 10mm vibrating pancake motors from eBay and use them in haptic eTextile and paper computing projects. I generally get 25 or 50 at a time and they cost about $.50 USD/ motor. Super Afforable!
Be careful when stripping the leads as the wire is very fine and its easy to inadvertently cut thru the wire rendering the motor useless.
Use the same blink codes as you would with an LED to turn the motor on and off.
Have fun!!!