Let's Build: How Low Can You Go?

This isn't going to be a full "Let's Build" instead, I want to talk through an idea that's been bugging me for weeks now.

When building a Shadowrun 5th Edition character you're given the option for "Alternate Gameplay" these modes, either high-power or street-level change the starting funds, and other limits for your character.

However, I was curious. If I really wanted a player to start at the bottom, and work up, what's the most restrictive set of limits I could place on a character and still have the game playable?

Why would a GM do this? Well, I wouldn't, usually. But, if I was running a group that really wanted a challenge, or I wanted to focus on a group building up their assets as a unit, and not as a group of individuals then imposing harsh starting conditions has some merit.

I've not gotten through the idea yet but I wanted to leave this here, both as a tease for my readers, and as incentive for me to chase this idea down and see where it leads!