In this video from the 2018 NAB show (at the 1:13 mark) the Sigma rep claims that the price of the new Sigma 105mm f/1.4 DG HSM Art lens will be under $2,000:
Recently a store in Lithuania listed the same lens for €1,999 or around $2,400 (US prices are usually lower). The Nikon AF-S Nikkor 105mm f/1.4E ED lens is priced at $2,196.95 in the US and I expect the Sigma version to be cheaper than that.
Additional coverage of the Sigma 105mm f/1.4 DG HSM Art lens:
Sigma 105mm f/1.4 DG HSM Art and 70mm f/2.8 DG MACRO Art lenses announced
Like: Sigma Facebook page | Join: Sigma Facebook group