As the one in charge of the Soul Trade in the Nine Hells, Mammon is incredibly wealthy. In fact, he might be the wealthiest being in all of Realmspace, save Mercantor. His devils will follow the regulations for how trade is supposed to be handled to the letter - always. But that still gives enough wiggle room for some bribes or political manoeuvring when needed.
Providing for himself is Mammon's most important goal and his body shows that. The fat bounces with every movement and he looks more like a pile than a humanoid, standing four metres tall and truly imposing. While his clothes might be simple, his skin is covered in plats of gold, bolted into his flesh. Surprisingly, Mammon's large body doesn't seem to prevent him from moving with great speed when he has to. More than anything, it contributes to the devil's strength and power.
Apparel & Accessories
Amongst his tattered cloaks, Mammon carries a book that allows him to determine the current value for any given thing. This includes the souls of the dead that arrive in the Hells. Besides this ornate book, all of his clothes are ones that might have been extremely imposing but are now decayed.
Mammon was one of the creatures Asmodeus first made in order to combat the demons when the Blood War first started. Back then, he was in charge of making sure everyone recieved the payments they were supposed to recieve. The transission to sending souls to the parts of the Hells they belong has been almost seemless from Mammon's perspective.
Greed fills every part of Mammon's being. He always wants more and he always wants others to have less. This doesn't prevent him from investing in the short-term, but he will want a good return on spent resources. And he has no interest in creating comforts that aren't needed.