Snowboarding is very similar to skiing. Both involve going down a snow covered hill at high speed. Both are mainly about balance. Both are only cheap if you live in the area, both are good exercise.
But snowboarding has you on one wide board, rather than one on each foot. The balance is now more about forward/back rather than side to side. That makes it significantly easier to do as the human body is designed to deal with forward/back balance more than side to side.
It is very very hard to stop while snowboarding, unless you sit down in the snow. So generally that's how they teach you to stop. Doing it too quickly is called 'falling' and hurts. Some people can stop without sitting down, but it takes a lot of skill. Many snowboarders get pads on their butt - both to protect it from a fall and from the cold. After about two days or so you learn to do it slowly, in a more controlled, less painful manner, and you start sitting rather than falling. This is a significantly FASTER learning curve than skiing - but you don't fall as much with skiing.
Snowboarding is slightly more male than female, but that is changing. Most people recommend kids start snow boarding later than skiing (age 7 rather than 3). Snowboarding is still a young person's sports - it's a relatively new sport and once your learn skiing you often have no desire to start over and learn a whole new sport. You don't see 60+ year old people snow boarding, but you will see them skiing.
Snow boarding also has the advantage of a more comfortable boot. It's not as rigid, as you don't need to be able to 'edge' the foot.
You can snowboard at most ski resorts - but you should double check with any place you go before heading there.
You can snow board at Mt snow, just like skiing: