To flyby or impact Venus varies from 3.45 to 3.6 km/s from LEO for the optimal time every 19 months. Mars varies from 3.55 to 3.9 km/s for the optimal time every 26 months. So on average, getting to Venus is a little less energy than getting Mars. But not by much. It could even be a tiny bit more in some years.
If you also want to get barely into orbit propulsively, the ranges are 4 to 4.7 km/s for Venus and 4.25 to 7 km/s for Mars.
Mars is more variable than Venus due to its much larger solar orbit eccentricity (0.09 vs. 0.007).
At either planet, you can aerobrake down to the desired orbit. Aerobraking has been demonstrated at both. Or you can aerocapture directly, with just the flyby costs above. Aerocapture has never been demonstrated, but there are no hurdles that would prevent its use in a mission, other than developing an adequate heatshield for Venus (much higher entry velocity). However you incur the substantial mass penalty of the aeroshell, a cruise stage that is discarded before entry, and the structure and mechanisms to discard the aeroshell and deploy the enclosed spacecraft. Aerocapture at neither body appears to be a win if you can afford the time to aerobrake, measured in months. (Aerocapture is mission enabling at Uranus, Neptune, and Titan.)