D90 is one of the best DX format bodies you can get. I've seen a few lightly used ones sell for $500. There are lots of the "lens kit" lenses kicking around for sale as well, usually very cheap at $100-$200 or so. These are the ones like the 18-70, 18-135, 18-55 and so on. I would go this route over the D3100. 12K shutter count BTW is not very high when it's designed for 150K +, I doubt you'll ever use it up. $600 for what you've listed sounds like a smoking deal.
However keep in mind a macro lens is going to cost you over $500 so if that's your main intention you might want to consider a cheaper used body like a D80 or even D70s.
Last edited by sphelps; 06-13-2012 at 09:22 PM.
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