Je pensais que tu étais sans le sou.

Sentence Discussions French
#1
English Translation

I thought you were broke.

le sou nm familier [argent] = penny, cent US
être sans le sou = to be broke
je suis sans un sou = I haven’t got any money (on me)
ne pas avoir un sou vaillant : elle n’a jamais eu un sou vaillant = she never had two pennies to rub together
un sou est un sou = a penny saved is a penny gained
©2014 Larousse

#2

I don’t think I have heard this version of the idiom before, but larousse reports it, so it must be used somewhere.
I usually hear/ use it as “ne pas avoir un sous” or, alternatively, “ne pas avoir un rond”