How much is my Nikon d3000 worth?

I've had it for about two years, rarely used. Almost new condition. Hadn't used it in months and I noticed nothing I can reach to clean is dirty, but there's a fog or smudge when you look through to take a picture. Pictures come out perfect you just can't see if you're focused when you take one. Inputs? Does it just need to be cleaned or what?

Yea, you need to get that fixed.

Otherwise, you should be able to get $250~$300 for it.

The D3000 was obsolete the day Nikon released it because they didn't include video capability and live view. Its initial replacement was the D3100 which is now selling for $446.95. You might get $200.00 for your D3000.