A couple there you could look for not sure what communication they would have with your camera, a pity @Bill16 isnt about as he uses one,i think the 105
at that sort of price i would go for it.the drawbacks are; noisy af, it doubles in length at macro distances and can hunt for focus. it can have communication problems with the nikon d90.......... giving a false low battery warning.nice and sharp with good performance stopped down further than most macro lenses.a great starter lens for macro, great for portraits too.
I have the non-ai converted to Ai Nikkor 105mm micro lens and is a little larger diameter than an ai lens of the same type. Ai lenses tends to be cheaper than newer models and work pretty well though it is all manual and has to be used in manual mode. It also isn't 1:1 ratio so you aren't getting the advantages that the newer AF and AF-s micro offer. I paid about $200.00 for my 105mm and a used AF 105mm micro f2.8 runs about $400.00-$500.00 . The better AF-S 105mm micro seems to be about $800.00.
You can get 1:1 ratio with the Ai 105mm micro, but you would need to get an extension tube, but it takes a different method to get the focus on the subject and is harder in my opinion.
I would recommend a newer lens choice if finances allow. But even without being 1:1 ratio the ai 105mm micro can take some great shots in my opinion, and is well worth buying if you can't manage to buy one of the newer micro lens choices.
A couple there you could look for not sure what communication they would have with your camera, a pity @Bill16 isnt about as he uses one,i think the 105