This camera, used is going for $300-$425 depending on the condition. Currently Keh.com, my favorite place to buy used gear, has used D3100’s starting at $325. Craigslist in my area has D3100’s priced around $375. Both these kits come with the stock 18-55mm kit lens, which is a good lens, but not great. Since you’re saving up to $275 you can spend getting the best lens for this camera, and that would be the Nikon 35mm f/1.8G .
This lens gives great bokeh ( blurry background ) and it costs just $200 brand new! Not only does it give your pictures that sexy bokeh, but it this lens is about twice as fast as the 18-55mm kit lens, which translates to 4 times the light! This means that if you take a picture in a darkroom with this lens, versus the 18-55 your pictures will be less grainy, and have have less motion blur. Trust me if you buy a Nikon D3100, your first purchase needs to be this lens. What does twice as fast mean? Take a look at the images below to get a better idea of the difference between f3.5 and f1.8.
Above is a picture of Momo taken at 1/60th of a second f1.8 ISO 2000
Above is a picture of Momo taken at 1/60th of a second f3.5 ISO 9000
The difference is subtle, but if you look the reflection of the TV, and Momo’s fur, you’ll notice that at f3.5 the image seems a bit sharper. But looking at Momo’s paw, where it meets the couch, and the reflection in the window you’ll see more grain, and more noise.
So if you’re looking to get a DSLR, buy used and save yourself a boat load of money.