The GP was talking $500/month rather than $500/year. That's a fair bit of money. It's nearly half the wage of a US minimum wage worker (and over half their paycheck, once taxes are taken out).

Even if you get a $15 minimum wage (as some places already have), it's still asking somebody to put away 25% of what they earn. That seems very unlikely. Not impossible, but a lot of life circumstances could easily result in it being impossible.