You don't say where you are. Sears has a Craftsman fingerprint reader for $35 USD (less on sale). It can be easily hacked to allow fingerprint control of any switch or lock. I have one and it works quite well. My fingers are old and dried, and with my middle finger it works better than with my index finger.
Sears: Online department store featuring appliances, tools, fitness equipment and more
Here's a link to one project that hacked it: Biometric Projects (a sort of complete how-to) - All About Circuits Forum