The intersection of topology and magnetism represents a new playground to discover novel quantum phenomena and device concepts. In this work, we show that under certain synthetic conditions, a van der Waals single-crystalline compound $\mathrm{MnS}{\mathrm{b}}_{1.8}\mathrm{B}{\mathrm{i}}_{0.2}\mathrm{T}{\mathrm{e}}_{4}$ exhibits a net ferromagnetic state with a Curie temperature of 26 K, in contrast to the fully compensated antiferromagnetic order observed previously for other members of the $\mathrm{Mn}{(\mathrm{Sb},\mathrm{Bi})}_{2}\mathrm{T}{\mathrm{e}}_{4}$ family. We employ magneto-transport, bulk magnetization, x-ray and neutron scattering studies to illustrate the structural, magnetic, and electrical properties of $\mathrm{MnS}{\mathrm{b}}_{1.8}\mathrm{B}{\mathrm{i}}_{0.2}\mathrm{T}{\mathrm{e}}_{4}$. Our structural analyses reveal considerable Mn-Sb site mixing and suggest a recently proposed mechanism, where Mn occupying the Sb site mediates a ferromagnetic coupling between Mn layers [Murakami et al., Phys. Rev. B 100, 195103 (2019)], could be at play. Close comparisons made to an antiferromagnetic compound $\mathrm{MnS}{\mathrm{b}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ illustrate the subtle magnetic interactions of the system and the important role played by local chemistry. The appearance of an unusual anomalous Hall effect in $\mathrm{MnS}{\mathrm{b}}_{1.8}\mathrm{B}{\mathrm{i}}_{0.2}\mathrm{T}{\mathrm{e}}_{4}$ at low temperatures hints at a magnetic ground state different from other members of this family. Our results are an important step in the synthesis and understanding of magnetism in materials with topological characteristics.
