In Bustin' Out, we learn that Giuseppi lives out of his purple van. He uses it to travel around and to evade the police. This van is his most prized possession, to the point that it appears as his backdrop when you first talk to him. One of the most surefire conversation topics with him in Bustin' Out is to talk about his van. He's always glad to talk about his van. He also uses it in his moving business and his... other business. In Bustin' Out, every night at around 2 am, he parks his van near the docks, and sells his wares to anyone who dares to approach him.
As a shop, his van is referred to as "the Riddle Machine" - a reference to the Mystery Machine of Scooby Doo, which is also a strange van. In Scooby Doo, the kids seem to live out of their groovy van, traveling around and solving mysteries. Maybe Giuseppi sees himself as filling a similar role - traveling around in his van, and causing mysteries for other people to solve. Where did my bed go? The more you know, the more you don't want to know...
In The Urbz, he reveals that he called his van Tristam, and, as a vehicle, referred to it as a "she".
I used to own a van. She was a real beauty. I named her Tristam. Oh the times we had before the bank repossessed her.
Tragically, the van is no more. It must have been an endeavor and a milestone to be able to afford this van. Even at the height of his business, it's clear that Giuseppi was never rich, and only stole to make do - as proven by the fact that, when he was in jail, that was it for the van. It was his only major possession. And he lost it.
After the van is gone, Giuseppi tells you how wonderful it was to drive around in his van, completely free to go wherever he pleased, just a man and his van. Running from the cops, ah, those were the days. Now that the van is gone, he misses it. He longs for the van. It is so important for him, it still shows up in his conversation backdrop, as a reminder of all that he's lost. That van was a symbol and a means of freedom, and... it's over. He will never have that van again. Even in his later appearances in The Sims 2 for GBA and for DS, he has no van.
He also doesn't seem to have any intention to get another. It's that van or no van. Also, he needs to be able to eat consistently before he can think about buying a vehicle of any kind.