Extension tube for Nikon D3100?

Does anyone make an affordable extension tube for a Nikon D3100 that i can change the aperture with? I don't have an aperture ring on my lens and i'm working with like $70.

The only extension tube ai know of are for close up macro type photography. I have never seen any with aperture settings.

You'll probably need to spend a bit more than $70 for reasonable quality - http://www.ebay.com/...1019699330

These are cheaper and may do the job http://www.ebay.com/...0651405372

@Bernd - With some modern cameras without mechanical aperture rings on the lenses you need electrical connections in the tubes to change aperture, they also allow you to AF if the scene is bright enough.