A best bet is the Good Earth Lighting 1-Light Bathroom Vanity Light in Dark Bronze (pictured), model no. G01121-DBZ-I, for $49.75 with pickup at Lowe's. That's $149 off list and the lowest price we could find. This LED light purportedly features the output equivalent to three 40-watt incandescent bulbs.
Of note, prices may vary between ZIP codes.