the cheapest route is to get a cross lever either from nashbar or ebay (~$20 the set) and find a used brake caliper at your friendly LBS or off a junker bike from a yard sale. of course if you find a junker bike you can also snag the brake lever.
i spent more on cable, housing, and brake shoes ($12 total) than I did on lever + caliper (hard to figure out since the caliper was ~$2 and the lever came on a handlebar/stem setup from a garage sale for $5)
anyway, brakes and levers can be cheap/trashed as long as they work...the cable and housing should be clean and new-ish to be dependable.
aesthetics are another thing entirely. good luck!