I picked up a used Sigma 105mm macro lens on eBay a few weeks back.
The one lens missing from my kit since I switched from Canon to Nikon has been a suitable macro lens. I had this same lens in the Canon mount and loved it. Very sharp, easy to manually focus and quite sturdy.
The one I got on eBay was a total steal for the price. I’d been watching the eBay action on these lenses for over a year and when they did come up for sale, and that was far and few between, they were commanding over $350 used in good condition. I found this one for $179 and it is in near mint condition.
So today, I decided to do the lens micro-focus adjustment on my D750 and D810. The results were better than I could have hoped for, as neither body required an adjustment to the fine focus offset. Both cameras set to 0 offset on this lens. That means that I got a perfect focusing, near mint quality macro for next to nothing.
If you are exploring the lens market, I highly recommend searching for a used version of this lens. Sigma doesn’t make this model any longer and the folks who do own them hang on to them like they are gold. And for good reason.