"...How much money goes into the justice system when a person gets caught with a little bit of weed? Upwards to a grand in most cases, for the first offense!..."

I suspect that if you figure in the arresting officers time, the court officers time, the various folks in the DA's office time, the judge/court reporter/bailiff/various clerks time, "upwards of a grand" won't come close to covering it. The justice system does not make money, period...