Mountain Bike with a power meter
 

Do you guys think a power meter is useful for a mountain bike? I plan on riding my mountain bike on the road for training with a power meter. If I do this, do you think this makes any sense at all? Any insight is appreciated. I am new to this.

Yes, it makes sense, if you are intending to race your mountainbike. If you are purely after fitness or your goal is to race a road bike, then you should use a road bike instead. While there absolutely is a lot of crossover skill (pedaling :D) between road and mountainbiking, your posture when sprinting and climbing are different enough that you would want to practice on the appropriate bike.

If you are talking about training with power and not racing, I would say that there are some road cyclists who do that and probably close to zero mountainbikers. I guess it does depend somewhat on what you're using for power. So, what are you planning to use... a Powertap?

I like gadgets and technology. If you like to track your progress in training or see how much power is required on a climb, I think it would be great info.

I personally don't know any off roaders who have one. My heart rate is the best indicator to me that I am maxing my effort.

Then again, my favorite shirt is: "The Older I Get the Faster I Was!"

Take the money and buy a used road bike instead.

Yeah, you won't get anything super high zoot, but you can get something decently used that you can crank miles on. That will benefit your fitness way more than a power meter will.