Adorama has a deal on the Sigma 70mm f/2.8 DG ART Macro Lens, you can save $70 and get it for only $399.
To see the discounted price, use the coupon code JULY4TH19 during checkout. Sigma 70mm f/2.8 DG ART Macro Lens $399 (Reg $469)
It was a bargain at US $469. My copy is quite nice - somewhat slow but accurate AF, even for macro, but very sharp. The two negatives are the extending tube (likely to inhale dust) and the fiddly manual focus (due to focus by wire).