>>49207709Trainers earn their living by participating in official competitions and whatnot, so yeah, Ash probably earns prize money and stretches it to survive, since he's not a big-league trainer. This is explained in Shudo's light novels, which are based on early anime scripts. Since the anime was under close observation around that time, this can more or less be assumed as true, even if it's never really outlined by the anime itself for some weird reason.
With that being said, I have always assumed that
>>49207785 is correct and that the Trainer Card entitles its carriers to certain facilities and benefits that basically keep them alive. Early concepts for the Pokemon Center depicted it as a hotel, so I'm fairly confident my hypothesis is correct. But by all means, feel free to bombard me with
>Headcanon. 
