A couple of years ago, my office mate introduced me to a 3D software developed by Google. I was surprised by its versatility but was dismayed about the fact it didn't support some lighting plugins back then.
I practiced on some of the online tutorials back then. I found the program to be very user friendly. It only takes a couple of days for someone who has no background in 3d modeling to learn this program. I never realized the true potential of the program until I saw most of my former classmates using the program in their renderings.
Lately, I started using Sketchup again. Its been a while since I last used the program. I needed to practice it again. I'm relearning the things I've learned back then and discovered some new things along the way.
If you are interested in learning 3D modeling but don't have the patience to go to school. I suggest you learn this program through online tutorials. It's easy to use and a great tool to help you with your designs. Here are a couple of links to some tutorials in Sketchup: