try: http://www.chess.com/store/wholesale-chess
people seem to like them :)
also, here is a list of all major clocks: http://www.chess.com/equipment/chess+clocks
i recommend you DON'T get an inexpensive clock if you can splurge and get a chronos! if not, the saitek competition clock is a good budget clock.
Where is a good place to get an inexpensive tournament style chess clock?