There are many camera owners who like to have the latest version of their favorite camera.
They often sell the old camera so that they can afford the new one.
If you can get a used camera from such a person, you could get a bargain.
Each time a new model comes out, they add more bells, whistles, and megapixels; but the overall image quality is seldom improved.
If the older model has the features you want, it will make a good first DSLR for you.
I still use a Canon 20D and find that it works for me.
They have not added enough bells and whistles to make me want to upgrade yet.
As long as you pick a used camera that is in excellent shape, I see no reason not to buy a used camera.
I'm upgrading from my point-and-shoot digital to an SLR. I have a fixed amount that I can spend. Is it better to get a new, entry-level camera (canon rebel or nikon D40x), or get a used higher-end camera (canon 20D or nikon D100)? The current one I'm considering is a used higher-end. It seems like a better deal, but its three years old, so I'm not sure what to do. How much has technology changed? Any thoughts?