Wooden ramps may be cost effective if 3-inches high is all you need. But if you want a 10" high ramp that you can safely work under with a 2-piece design that is easy to transport and store, you won't find a better alternative than Race Ramps.
If you build a 10" high ramp out of 2 x 10s you are likely to break your back trying to lift it and there is no way you are going to transport it in your car.
I am sure a lot of people who get Race Ramps have buyer's remorse, especially when their spouse finds out how much they cost. But after you have used them once a big smile will spread across your face and you will be the envy of your car club buddies.