Appropriate first dslr before upgrading to Nikon D3100?

Hi. Thanks a lot for taking the time to answer my question. (=
So the thing is, I've always wanted a Nikon d3100.Im 15 but still a major photography buff. I've been promised my first dslr by the end of this month. But I just realized that at the rate I use a camera, the brand new d3100 will get spoiled very soon.
So can you suggest a cheap dslr that I can buy secondhand or new just to learn the basics? I plan on selling it later to buy the d3100.
This way the d3100 can last longer.
I'd prefer it to be a nikon so I can keep the lens for the d3100. But I guess anything works.

Why not buy a DSLR and look after it properly - then it will last you a good few years! The D3100 is a basic entry level DSLR - you can't get any lower in Nikon's current range.

Why do you need to buy a DSLR and learn how to use it, then sell it on?

Why not buy a good DSLR thatll last you for agess, buy something abit better than a D3100, they are quite amateur, buy a D5000.

That being said, you could buy the D3100, and put more money into the lenses, the lenses are what produce a good quality picture, not so much the body.

If i were you, id buy a DSLR, and just stick too it, you don't need to sell it so quick, the D3100 is a good basic dslr, which is good for learning with, but it is also good to carry on with once you know how to use it.

A camera is not a perishable product like food, it won't spoil.

Like DB2 pointed out, the D3100 is the entry level camera for Nikon (consider it to be a bike with training wheels).

By the time you can buy a used Nikon DSLR to learn how to use it properly, the D3100 will probably be replaced by something else. Besides, more than likely the used camera you buy will have the same basic "kit" lens that would come with a new D3100.

Nikons are probably the most durable of all entry level DSLR cameras. If you can't make that survive there's no point really in you shooting a DSLR

While I agree with the comments made by everyone above me, I will answer your question.

If you can find a "low mileage" Nikon D70s, you will be able to use it for a couple of years while learning about digital photography. When you upgrade to whatever new Nikon is available at the time, you will already understand the way Nikon thinks about control layout and menu terms.