Forgot to answer.
Is it possible to be a successful at home trader with no other source of income who began with modest means? Yes! But I highly suggest at least 30-40k to begin and 6 months living expenses.
I agree having some $$ put aside for expenses. Moving from a job with a fixed salary to trading where there is no guarantee of any income (and possibly even losing $$) is a big adjustment and one doesn't want to put any excess pressure on themselves early on in their trading career. It's important to minimize trading mistakes early on and I started by taking small profits to help build confidence. Knowing you are picking profitable trades (even when the profits are small) helps to see that you can succeed over time. On the other hand I've seen newer traders get too emotional about trades or trade too big a size and suffer losses big enough that they eventually threw in the towel.