I agree with stoneten. Look for a good quality product - i would also suggest not shopping at a general 'sporting goods' store, go to a local bike shop, you'll get a quality product from just about any of them. The benefits will be amazing, it will help with the soreness, and it'll product your junk on long rides. and if you go with the spandex/lycra they will stream line your body along with wicking away sweat, (goodbye DUCKBUTTER.) but you can buy baggy bike shorts too if you don't like the idea of wearing spandex.
enjoy your rides!