I think it’s great that you’re willing to offer help to those in need. $500/mo is enough to really help you out with expenses, but likely cheaper than they’re able to find elsewhere. Especially considering that the environment is supportive and safe for them.
That being said, I would strongly recommend getting them to sign well-defined contracts that you get from a real-estate lawyer to help shield you in the case of it turning sour.
My coworker just got finished with a year-long legal battle trying to kick out someone that he allowed to bunk in a spare room for a few months (completely free). Despite them not paying room or board they were classified as tenants and therefore had legal protection that they took every advantage of and made my co-worker’s life hell. I’m all for strong tenant protections, but there’s always going to be the exceptions that abuse the system. I would follow your heart on the payment side, but insist on contracts to protect your livelihood. Don’t let a good deed ruin you.
Subway and most buses $2.90 a ride, and if you use the same payment method it has a maximum combined fare of $34 per week. That means that if you pay for 12 rides, any more rides are free within a 7 day period.